Wueenie, as far as I know there is only one DIS meet in September, which is the Dessert gathering at Epcot on 28th. We are missing that too, which is a shame as I think it would be fun.
Tbh, though, as we are only going for a week, I'm not sure that I would want to do a meet unless it was perhaps a drink or something in one of the parks. Maybe next year