There is a field called OES (Osceola Extreme Sports) in Kissimmee and very easy to get to if you're staying near Disney. They have some woods fields and both airball and Xball fields. It is also our home practice field so depending on when in September you're visiting we're likely to be there on the weekend and you're welcome to drop by and say hello.
Fishing: not much help there excepting Boca ain't nowhere near Orlando and Disney.