That might be cutting it close, especially if youre flying on a cruise return day (ie Sunday). Ft Lauderdale in my experience cant handle a bunch or cruisers flying home. It was a nightmare! It took us at least an hour and a half just to check in, then we had to haul our luggage over to screening (not easy when people are everywhere-you couldnt move) and stand in line again, then stand in line at security. Employees were screaming at people to make openings in lines so people could walk through.
Plus with security these days, I would try for a later flight just to be safe, or fly out of Miami. The ship may dock at 8, but there could always be a delay (weather, inspections, traffic, etc). You can request a color tag for one of the first to get off the ship (you will fill out a form stating your flight info-put down that its early). You will have to find your bags, clear customs and get transportation to FTL. There could be traffic delays on the way there too. Just my opinion.