We were there last year from Sept 17-25th and had a great time.
Due to the Hurricane issues, the parks were empty. It got to the point where we wouldn't enter a line if it said 20 minutes or more, not even for the top attractions. One day my Brother-in-law and I rode MS and TT, 3 times each before 11:00 am.
We had one day with some rain, but only for a few hours. Temps were warm, Park hours were shorter but still sufficient, and waits were minimal.
We had planned on going again this year in September, but it will depend on whether we move to NC in August. If we do, we will probably delay the WDW trip until November.