I am scheduled on a return flight to fly from Ft Lauderdale to Birmingham AL through Atlanta and will be checking a bag. My son needs me to babysit in Atl on the day we are connecting through and will drive me home to Birmingham the next day. If I don’t fly that last Atl-BHM leg, can I just route my bags to Atl when I am leaving Lauderdale?
Typically you can't do this.
Getting off at a layover is explicitly "forbidden" in the Contract of Carriage of most airlines. This rule is to protect certain pricing policies and to prevent customer to save money through "Hidden City Ticketing".
The "correct" way o do this would be to change your ticket to return to Atlanta, and not Birmingham. Chances are the airline will charge you a hefty fee for this.
You can try to sweet talk the check in agent into routing your bag to Atlanta, but it's unlikely to work.
The only "loophole" would be an international arrival, where you have to pick up your bags anyway, but for a domestic itinerary, this will probably not work