Hi Rocio! In the past few years, Disney has extended the popular
Free Dining Promotion into October, so it's certainly possible the current Free Dining offer may be available past September. In previous years, the October Free Dining promotion often wasn't announced until mid to late summer, so it may be a few months before we know if Free Dining will be available with October vacation packages.
One of the reasons I love visiting Florida is that it's warm and sunny for much of the year, and September is no exception. The September temperatures are similar to those of the summer, with highs around 90 and lows in the 70s. September generally sees less rain than the summer, and the attendance levels in the parks are generally very low in September, which makes it a great time to visit if you don't want to deal with lots of crowds and long lines. If you don't like heat, October is a little cooler, with high temperatures averaging in the mid 80s and lows in the 60s.
Come visit us again at the Moms Panel if you have more questions! We'd love to help!