We're going 9/15-9/21 and I'm assuming the parks won't be too crowded because when I called reservations and dining, I pretty much had my pick of everything. The only one missing school is our 6-year-old who is well ahead of his class and will be fine. I would much rather pull the kids out in Sept. during "review" week than go in the middle of summer with a 4-year-old and 2-year-old as well. We went 2 years ago from 9/21-9/27 and there was absolutely NO ONE there. Of course, they didn't have the dining plan then, but they had some sweet deals on rooms. I'm sure you'll be fine. Just be glad you're not going over the holidays!