Last weekend we were supposed to get some 12 inches of rain here in Alachua County due to a tropical storm. We hardly got any rain at all.
These storms are extremely unpredictable, and nobody knows exactly what they are going to do more than a couple of days ahead even if they are well-organized. It'll be a few more days until we know whether or not it'll affect Florida at all.
Since Orlando is in the middle of the state, it doesn't get the strong winds that the coastal areas close to the eye wall get, but there might be very strong and sustained rain and quite strong winds. Thunderstorms and tornados are possible. Should you be there during a hurricane, it's a good idea to keep a close eye on the weather channel. The parks will remain open unless things get really bad, although some outdoor attractions like Test Track and the parades will probably not be operating.