Maybe I am did not make my question clear, sorry. I plan on being on time

For Cozumel, the time listed online now for my cruise in December for Fury Catamaran is 8:15am. I was just wondering if that was the time it actually left, so will the ticket in the room might say meet at 7:45AM.... or is that likely the time to meet 8:15am, with actually time departing once everyone checks going to be more like 8:30/8:45am? Does that make sense??