We were there also the week of Labor Day and it was great! The weather was warm but the crowds were very small - we like to go this time of year for this reason. Dh walked on every ride (Splash Mtn, Space Mtn, Expedition Everest, Tower of Terror) and the only one they had to fastpass was Soarin.
The restaurants were busy, although I noticed the worst was Coral Reef (we had lunch ADR at 3pm). They said they were booked solid until October 9th when we asked the waiter about it.
Have fun! Enjoy!