I know there is a guide out there just for adults, and frankly, there is alot for adults to do. First you would need to stay at a more upscale resort, less child oriented, imo. I like the Grand Floridian. I could just hang around that pool and spa for the week.
Epcot is really more adult oriented than any of the other parks, with the Animal Kingdom coming in close, and MGM after that.
Great restaurants are everywhere in the parks and resorts, and downtown Disney is a shopping mecca! There are several restaurants here also, from the House of Blues to Rainforest Cafe to Bongo ( Gloria Estefans' place). Also, going in September is the quietest of the months to go. We have been there twice in September and there are no lines to deal with to speak of.