I think you got a problem, because Orlando is the closest airport to Port Canaveral ... Ft. Lauderdale is about 3 - 4 hours away, depending on traffic and how long it takes you to get the rental car.
I thought of flying in the morning of....very very early, but changed to flying in the night before, after worrying about all the things that could go wrong on my flight.
You still have about an hour to get to the port from orlando. Some say if the toll road is fixed by then, they can do the drive in 45 minutes... I didnt take the toll road, and it took me over an hour.