Washington State and a number of others require a CDL for any bus that seats 16 or more including the driver.
Laws can vary considerably from state to state. Check out YOUR STATES laws.
Don't blindly follow advice from me, in Washington, when it comes to laws in Florida. There are some folks here that work under the impression that the laws and practices in their state must apply in all states.
That said, many folks choose to bend the rules in order to get the bus home.
Regarding auction pickup. I have only seen a few auctions that require a CDL for pickup. If you are stuck on a bus that has that requirement then you may consider hiring a driver to get it off of the lot.