I agree that September is too hot to tent camp at the Fort. At least for me. But, I will tell you that the Fort has tons of tent campers during the summer months. So, if you are up for it, go for it.
Do not worry about the hurricanes. In the remote chance that the Fort is in the direct path of a hurricane, the Fort will be evacuated (it happened once to me). And by evacuated, that means everyone has to leave. Tents, campers, motor-homes, guests in cabins, everyone. And . . . if that happens, the management will put you in a WDW resort hotel room at no extra charge. As I said, it happened to us one October. We were given a room at what was then called Dixie Landings. The weather was pretty crumby, but at least we weren't in our camper. When the storm passes, you are welcome to go back to the Fort, or you can cancel your trip with no penalty.
And I should add that despite the recent activity in the past few years, it is rare for WDW to be in the direct path of a hurricane.
TCD