At present, if you are using
DCL transport from the MCO Hyatt or a WDW resort, you will be automatically given an early PAT and early boarding group without choosing one. However, if you are transferring with DCL transfers from MCO (not Hyatt) then you will need to pick a PAT and could be assigned any number of boarding groups. Make sure your reservation shows Hyatt as your transfer origin, not the airport.
When we were there last month, the piece of paper we got when we checked in said to meet down in the lobby of the Hyatt at 8:50 for a 9:20 departure so we did that and the place was absolutely MOBBED. The first bus departed around 9 AM and I imagine those people were there LONG before 8:50. We ended up being on the fifth bus at around 10:15 or so. It didn't really matter. Either way, we would have waited. We arrived at the port at 11:15, boarding began around 11:45. Our boarding group, group 5, was called at 12:20.