Orlando/Port Canaveral Disney transportation question

We (2 adults) are first time cruisers and are planning our transport to and from Port Canaveral this Feb and after being very confused by transportation options on our own, we decided to reserve Disney’s ground transport just to get that over with. BUT we booked that AFTER we checked in and got port arrival group 14 (12:15pm…is that very late?)

We are staying at a hotel close by airport (but not the Hyatt) the night before so are wondering if we could hop on an earlier shuttle from airport (like 10am). We were just planning on heading back to wherever they pick up people at the airport. Will they let us on whenever or will they make us wait for a later shuttle since we might arrive earlier than the boarding time? If we do happen to arrive early to the port will they turn us away until 12:15?

What should we expect for Disney ground transportation in general, for embarkation and debarkation? Is it true we will be asked to leave the ship early since we reserved Disney transport back to airport?

Sorry, we have no idea what to expect and had trouble finding more info! Thanks so much