I had no problems making it to FLL for a noonish flight after a PoM cruise, but it was on Norwegian and I did self walk-off. I also had a friend pick me up at the port terminal at 8am. We had plenty of time to stop for breakfast, and then for me to clear security at FLL and be bored for hours.
If you are not doing express walk-off, and you have to wait to find your luggage and you end up in the longer/later customs line, AND you have to try to coordinate with a shuttle service, you may end up cutting it a little closer. I also had good traffic luck, but it was a weekend day and we took US1 for some of it. A weekday arrival and I-95 could mean gridlock.