They won't start boarding the ship until at least 11:30. We've seen boarding start as early as 11:40 and start as late 12:05. So even if you are there by 10:45 you won't get on until probably noon or a bit after since they first board the family of the day, then concierge, then start calling boarding numbers every 5 minutes. You'll just spend time sitting in the terminal. With a bus check-in time of 9:30, you'll likely be arriving before they start boarding. Your PAT is early because that's what they do when you take the bus from the Hyatt. The last time we took the bus from the Hyatt, we were on a bus a little after 9 am and sat in the terminal for almost two hours.
Chances are, if you show up early to the Hospitality desk, they'll just make you wait until Silver is called and even if they check you in, you'll probably need to wait until the bus for your CC level is called.