Two questions:
1. Are you flying out of MIA or FLL?
2. What day of the week do you disembark?
If you are going from port of Miami to MIA, you should be fine. Weekday or Weekend.
If you are going from port of Miami to FLL ~ Weekend, be first off and you should be good. Weekday, you are contending with rush hour traffic. I likely wouldn't risk it.