I also wanted to chime in on this...
We stayed at POR from 6/3 to 6/11 (last week). My son had a pirate cruise on Wednesday, 6/8 at 9am.
Since the parks are opening at the same time (9am)...be sure to be waiting for a bus early....8:15am at the latest.
We were running late...so, I didn't wait for the Magic Kingdom bus. We grabbed the first bus which happened to be MGM. From MGM, we took a bus to the Grand Floridian.
I originally wanted to take a bus to Magic Kingdom and then take the monorail. That would be your easiest bet.
The main thing I wanted to convey is don't worry about running a little late. I was worried because we arrived at the Grand Floridian at 9:05am. We rushed to the marina and arrived there at about 9:10am to find that they were still registering people....fixing the kids' hats...and putting on life vests. The actual boat did not leave the dock until 9:30am and returned at 11:30am on the dot. Even at 9:30am...when the boat was departing....a child was coming in for registration. They registered the child and another cast member took him in another boat (Boston Whaler) to meet the "pirate ship" at the first stop.
My DS5 loved the pirate cruise.
I wanted to share this information because we originally had a PS at 11:30am at Whispering Canyon for lunch...thinking that the pirate cruise would end at 11am and we could catch the monorail to MK then the boat to Wilderness Lodge. Well, we had to move our PS to Noon instead and we were still a few minutes late.
So...if you're running a few minutes late....don't worry about the boat leaving without you. It doesn't seem to leave until about 9:30am anyway.....
POR's buses are slow because they make 5 stops....first at POFQ, then at the South Depot (main bus stop at POR)...then, the West, North, and East Depot...before heading out to the the Magic Kingdom. I would be out waiting for a bus no later than 8:15am if you want to be to Grand Floridian by 9am.
If you are staying at Oak Manor or Magnolia Terrace (like us)...the East Depot is the closest bus stop....but, it's also the last bus stop and the bus is often full or standing room only by the time it gets there. If you are in this situation, I would recommend walking to the main building and catching the bus at the South Depot (2nd stop for the bus after POFQ). This way you will not be passed by because of a full bus and chances are you won't have to stand on the bus either.
If you have any other questions...feel free to ask.
Speed