Everyone must be off the ship by 9:00 am the latest, so even if you left the ship then, the ride is only about 60 minutes give or take (depends on fast the bus driver is....) you would be at WDW by about 10:15 or so.
The buses do wait until they are pretty full, but at that time in the morning they fill up very quickly so you should not have a long wait at the terminal before they head out to WDW.