Welcome to the Dis!
First off, I think 8-9 days is a good length. We usually do 10-12 because we get some time to rest in there. Our first trip we did 7 I think, and I felt like I had to go, go, go to try and fit in as much as possible. Now we do longer trips and take naps and such as needed to make it through our time there. I decided on 12 days this time b/c I still did a bit too much with 11 days last year and ended up getting sick. My body reacts that way though. If I do too much, I get sick. So, this year I am going armed with an antibiotic I filled for a kid that didn't end up needing it. Z-pack baby!!!
Yes, Harry Potter is at Universal. I have never been b/c I am Pooh sized and don't want to go until I can fit on the rides. My parents will occassionally take off from Disney and go to Universal and the beach and the Kennedy Space Center. I have not personally done that so I cannot be a help there. I dedicate every day I have to Disney. That's just me though. My family loves Disney.
What I would do first since you have decided your time frame, is to start checking out where you want to stay. I am going to assume you will stay on property for your first trip b/c it is very magical staying on property in my opinion. Of course, you have the option to stay off property. I choose not to, but again, that is a preference of mine. We love staying immersed in Disney. It is really easy to go on the Walt Disney World website and start looking at resorts. You have to decide what level you want to stay at: Value, Moderate, or Deluxe. We have only stayed at Moderate: Port Orleans Riverside and Coronado Springs Resort. This year we are staying at Caribbean Beach Resort and trying one night at the New Art of Animation Resort. It will be our first time at a value.
The next question for you will be: Dining plan or no dining plan? Dining plan is available to onsite guests, and if you say yes to the dining plan, which one would you choose? We like the regular dining plan. We always go during
free dining so we never have to pay anything other than tips or if we eat anything off plan. The regular dining plan gives each member of your family one quick service meal per day, one table service meal per day, and one snack per day. Quick service is similar to fast food, but the options are broader. You can get ribs and such at some restaurants. You can use your dining entitlements as you wish once you get there. You can do all QS/Counter Service in one day, and do two table service meals if you wish. It is up to you. We like to share our CS meals with each other so we can spread them further. For instance: We like to eat at Pecos Bill's in Magic Kingdom. They have a chicken wrap that my hubby and I will split in half. Then they have a toppings bar that we can use to add to our wrap. We add on as much as we want, and for two people, we only use one entitlement. That gives us an extra to use on a breakfast. We manage to eat breakfast every day by doing this. Table service entitlements/credits cannot be shared. You can use 2 TS credits to eat at some places like Cinderella's Royal Table in the castle and such though, so as I said, u can use them as you wish! Dining reservations can be made 180 days out for resort guests, and on day 180 you can make +10 days worth of reservations, meaning that you can make up to ten days of reservations from day 180.
What I do from a year out is I subscribe to TouringPlans.com. It is $10 for one year, and they predict what crowd levels will be for one year. So they predict up to today's date in 2013. There are some sites that are free, but I like this one. I track my dates and they send me emails when something changes with my crowd levels. They adjust based on events, specials, etc... I use the crowd levels to plan my park days. We don't use hoppers, so we dedicate the whole day to one park. A lot of people swear by hoppers, so you may wish to use them. I just like to dedicate my time to one park and not waste valuable park time moving to other parks. Again, just our preference. Based on the park levels, I choose what park to go to, then I decide what restaurants we want to visit while there. We like eating table service. We think of it as a part of the experience. I don't know if I will ever go without the dining plan. Based on where we are going what days, we choose our restaurants and cross our fingers in hopes of getting what restaurants we want when our ADR (advance dining reservation) day finally comes! We got everything we wanted without issue for this trip. Again, the WDW website is a great way to check out restaurants. I also use Allears.net to look at menus and such.
Here is the link to WDW for resorts:
http://disneyworld.disney.go.com/resorts/
Here is the link for restaurants:
http://disneyworld.disney.go.com/reservations/dining/
And here is the link for Allears:
http://www.allears.net/index.html
I know this is still a lot of info, but let me do this: I will show you my itinerary so you can get an idea of what some people do when they are there. Again, mine is all Disney, all of the time, so you will be on your own there!
Day 1: (3) (parentheses tells what the overall crowd level is for all of the parks that day)
Flight with arrival around 11
Arrive at CBR around 12:30
Lunch: CS (probably at CBR food court)
EPCOT: (1.5+) 9 AM-9PM (The parentheses have the crowd level out of ten for that park. The plus means it is a best park day as chosen by Touringplans.com. I always list the hours of the park we are going to even though we may not stay that long or be there that early.)
Dinner: CS at EPCOT
9 PM: Illuminations
Day 2: (4)
Open AM schedule
DTD (Downtown disney)
Lunch: T-REX 1:00 PM
Magic Kingdom:
MNSSHP (Mickey's not so scary Halloween Party hard ticketed event.) (1.1+) 4 PM-12 AM
Dinner: Counter Service
8:15 PM, 10:30 PM: Mickey's Boo to you Parade
9:30 PM: Happy Hallowishes
Day 3: (8)
Animal Kingdom 8 AM-6 PM EMH (4.6+) (EMH is extra magic hours where resort guests can get into the park early or stay later than other guests)
Lunch: CS
3:45 PM: Mickey's Jammin' Jungle Parade
Dinner: O'Hana at the Polynesian Resort 7:05 PM
Day 4: (2)
Hollywood Studios: 9 AM-11 PM EMH (6.3-) (the minus means it is a worst park day as chosen by TP. We made a conscious decision to hit a worst park day b/c it fits with our schedule)
Lunch: Fantasmic Dinner Pkg. at Mama Melrose (This is the way to go if you want to see fantasmic. Priority seating tickets are part of the package, and you only use one dining credit if you go to Mama Melrose or Hollywood and Vine) 1:45 PM
3 PM: Pixar Pals countdown to fun (super fun parade)
Dinner: CS
8 PM: Priority seating for Fantasmic (no waiting in line for 2 hours!!!)
Day #5: (6)
MK: 9 AM-12 AM EMH (7.6-)
Be there for rope drop
Appointments at 9:20, and 9:30 AM at Bibbidi Bobbidi Boutique and Pirate's League
Lunch: CRT (castle) 12:05 PM
3 PM: Celebrate a dream come true parade
-Midday break-
Dinner: Counter service
Late night EMH (LOVE, LOVE, LOVE MK at night! It is magical.)
8 PM: Main street electrical parade
9 PM: Wishes
Ok, so I won't give you the whole thing, but I wanted to show you how we plan our days out. Not everything I list we will attend, such as parades, but we know the times just in case. I hope that helps, and please ask us anything!