Whenever I've had an overnight international connection it's always been my choice if I wanted the bags checked through to the final destination or if I wanted them at the connecting city. Your best alternative is to ask they check them through to Atlanta when you are checking in, if they ask tell them you need them for your overnight.

Even if they do manage to check them through, you can probably just show up and pick them up at the airport when your flight is scheduled to arrive.

Also note if there are earlier flights from ATL to BHM before the one you are on, they may send your bags on any of them, so they could be sitting there for hours.