I have cruised out of Port Canaveral before on the Mariner. The drive from Orlando Airport to the Port is about 35 to 40 minutes. My rule is that I never book a flight before 12pm. This allows me for enough time to get off the ship, travel back to the airport and check in with my airline. My travel agent also recommends not booking a flight before 12pm. If I were you, to play it safe I would change my flight. Eventhough the ship docks at 7am, it takes awhile for them to unload the luggage and to get proper clearance for debarkation.
Arrive back in Port 7:00 a.m. On the Mariner of the Seas
Was told by Transportation company that I Probaly wouldn't make this 10:50 a.m. flight and should push back the flight till after noon.
What say you?
Have your travel agent find out the earliest flight for which Royal Caribbean will provide transfers to the airport, if you elect to use the cruise line's transfer service, then make sure that your return flight does not leave the airport before that time.
If the ship returns to Port Canaveral directly from a foreign port, U. S. immigration officials usually do not allow anybody to leave the ship until the entire ship -- that is, all passengers and crew -- complete immigration inspection. Thus, one uncooperative passenger who does not report for inspection can hold up the entire disembarkation process. If that happens, or if the immigration agents are slow in conducting the inspection (as happened on one of my cruises), you might not be able to leave the ship before 10:00 or later.