Hi Gayle,
I'm so glad you had a magical Disney World vacation! I always find that starting to plan our next visit makes the reality of returning back home less painful! September is a great time to visit Disney. Once schools are back in session across the country, crowds tend to be much more moderate, making navigating the parks a pleasure. In addition, toward the end of the month, while it is still usually warm, the weather generally is less oppressive than during the middle of the summer.
The International Food and Wine Festival at Epcot kicks off on October 1st this year. This is a fantastic special event, that is absolute worthy of a visit if your trip extends through October 1st and 2nd.
Historically, Disney has, indeed, offered some fantastic special packages during September, including free dining offers. There is no way to predict exactly when or which packages will be available during your travel week, however, if your heart is set on a specific date, I would recommend making a reservation, and then continuing to check back to see if a better offer is available for the dates you have in mind. I have successfully done this many times, including for free dining promotions.
Have a wonderful second trip!
Tanya