I don't really think you need to justify for the kindergarten teacher per say,...and I'm a teacher, but WDW is packed with educational opportunities!
I'll skip a few of the obvious ones, like asking CM's in the WS how to say, "thank you" in their native language.
Visit AKL. If you happen to be staying there, the storyhour tellers are wonderful. I think they are carefully hand picked by Disney and complete a careful apprenticeship. Talk to them after the story is over. If you are not staying there, try a meal there with time to explore the resort. Trying a new food is educational. (I prefer buffet Boma, where you can sample small tastes of new foods, and also get plain noodles. Sanaa might also be great!) Seeing the animals is educational, (at AK park, you can even get a card saying you completed educational activites. It's not always offered, so ask about it.) Beyond that, the resort is filled with African art and info about the folks who made it. Explore! Many resort CM's are from Africa, and will be happy to talk about their culture/homeland with you.
Do an autograph book. Your child will get much out of reading each name in her book. The characters also sign their names with hints: like Pluto always tunrs the o in his name into a paw. Being able to read each name will give your child confidence - and it's a great thing to share with the class.
If you happen to be driving to FL, strongly consider a stop in St. Augustine to see the fort there. American history books - even college level ones - love to completely IGNORE the history of Florida. St. Augustine was founded in 1565, contruction of her stone fort, which you can visit today, began in 1672. It's cool on SO many levels!
I'd personally skip the America show. Major events like WWII are condendsed into like 30 second segments. The Pilgrims are America's first settlers. It's highly sentimental; too much American mythology, IMO. Canada and China's shows are much better IMO. France's film is a bit of a snooze, but pretty. HoP is maybe a bit slow, but a better choice for American history. It's being redone right now - so maybe it has also improved!
Let Disney happen. The stimulation itself, it's hard to explain, but I've watched the kids in our family blossom from trips to WDW. After a trip, their voacbulary somehow expands as they try to describe what they experienced.
There are lots of surprises too. Once for short time, Disney gave out special rainbow glasses for Fantasmic. It may have only been one week. They were just like those X-ray specks they used to have when I was a kid. Anyhow, my HIGH SCHOOL students were fascinated with them! They studied how they worked! The student who brought them back did a whole research paper on WDW!
Maps. Let your child read the park maps. Even without the map - even well after the trip - help her create a mental map of WDW. What ride is next to the Tiki House? Which park? Which 'land?' This is not the kind of lesson that schools are great at covering (Esp. now with the focus on READING all the time) - but mental mapping is an extremely useful life skill!!!!!! Looking at actual maps is a good way to practice reading, too. Another thing to try - if you haven't yet - is Google Earth's special WDW map. You have to download it specifically, and it hogs lots of memory, but it is SO COOL! You can virtually walk around WDW, one setting lets you see the buildings as if you were literally walking around WDW (Like certain video games create virtual worlds).
Be sure to see Living with the Land ride and spend time looking at the fish in The Living Seas. DO see Turtle Talk, not only is the show technology cool - but the jellyfish tanks in the waiting area are very cool and rare! Jellys require a VERY special kind of tank, and they are very expensive. Jelys can't hit any sharp corners, so the tanks have to keep a constant gentle flow. Plus they have very specific dietary needs, and are very hard to keep in captivity. The technology of the tank is cool in itself. (though your 5yr old probably won't appreciate that - you should!
) If you happen to go at teh right time, you might see the fish in the big tank getting fed, or divers in the tank. One favorite in our family is buying one of the little hydroponic plants they seel next to Soarin'. It's a tradition. They will live a good while if you don't open the jar. I had a mini- vanilla plant last for years. Vanilla is NOT supposed to be able to grow at my lattitude! Go figure! My mom had a Florida "mini" palm from WDW that lasted over 25 years and grew to be seven feet tall!
Oh, also in the LAND, you can take the Seeds tour. They make it fun for kids, and ifyou do any gardening yourself there is some great info. Plus the kids get to release ladybugs or feed the fish. It's VERY educational and only takes about an hour, I think.
All over WDW are quiet opportunities that may or may not happen. (Let the magic happen to you) Your child may get picked to be in a show, for example.
Do see the bird show in AK. I also think the Lion King show is an excellent example of acrobatics...La Nouba surely tops it. What you can accomplish with determination and practice.
Oh, and I've only touched the iceburg here. I personally feel I learned much from WDW about overcoming my fears. There is so much positive reinforcement in conquering a thrill ride. Beyond that, DIsney offers some excellent examples of ride technology. TTa offers the first example of a linear induction motor. Maybe physics is beyond your five year old- but rides are EXCELLENT examples of how physics work. SO MUCH engineering goes into every ride. Just thinking about some of the special effects, line management, crowd management. There are people who spend their whole life understanding traffic jams/crowd bottlenecks or chaos theory. Again, maybe too much for a five year old to comprehend the job of a civil engineer - but you're never too young to foster a sense of curiosity. The seeds of the world's most brillaint thinking were almost always planted through childhood questions.
Okay, I'll end there before I go too far off the deep end, if I haven;t lost you already...have a great vacation!
and we have not pulled the kids from school for an extended period of time in a while because its very tough to do as they get older, plus DW is a teacher and her schedule is limited to school breaks......we have pulled all 3 kids numerous times from school over the years for WDW trips between K-5th grade. We have always brought some material for the airplane ride that was similar to what they were doing in school (math sheets, vocab, etc). We have also always brought books to read for plane ride and resort down time.....other than that we were pretty low key about "homework" after all the kids are on vac. One thing we always did was have the kids keep a daily journal, they never looked at it as schoolwork, but it clearly helped with writing, thought process, etc. It also went back to school to share with teachers and friends. This journal was a recap of the day, favorite rides, food, memory, what were looking forward to tomorrow, etc. When the kids were younger it often consisted of just pictures, but the thought was there. We were just in WDW over Easter school break and DD (6th grade) still did her journal, of course this time she did it on dads laptop, added photos from our trip that we downloaded that day and even wanted to do a Powerpoint with music and flying entries!! I told to go easy, I was on vac too!!
We have never pulled them out of school before but we are doing it this year. Hopefully there won't be a problem. 
