They want everyone out of their cabins by 8:00 so they can start cleaning for the next group. First buses leave about 8 as well, some maybe even a bit earlier.
Note, you will have to take your own bags through customs (a porter is VERY convenient for this) and out to the bus to be loaded underneath. There is no luggage service from the port TO the resort like there is FROM the resorts.
Once you exit the terminal with your bags/porter there will be a CM who will direct you to the correct bus for your resort. As soon as the bus fills (time depends on how many are going to your resort) you depart and may make a stop at another resort.
MJ