I agree that you are cutting it fine. If your flight is on time, you go straight to the buses (not stopping for luggage), and have a bus leave immediately after you board, and have a quick check in at BLT, you would probably make it.
But flights are often delayed due to weather, you won't have your bags until after the cruise, the buses often take awhile to fill and you have multiple stops (BLT may not be the first stop).
I once arrived on time at 6pm and had a 9pm Chef Mickey ressie. I was doing a rental car and carryon bags. I barely made it. I had to go straight to the dinner still in my rumpled plane outfit and my bags locked in the trunk. Eventually checked in around 11pm.