If you are catching a noon ferry in Roadtown you should not need to leave TMM until 11:30. If you are nervous go at 11:15. I have no idea why TMM is saying 10:00. As long as you get to CA by 2pm you will be fine for the Delta flight.
Personally I would set up a pickup at 9:30 for the 10:00 ferry and arrive CA around noon. Store your bags with the cabbies and go have a nice lunch and relax a bit before the airport adventure!
G