Use a return bend out of a standard shoe, then a pressure tee after that. The deeper glue joint of the pressure tee is necessary for this application. Leave the top of the tee open, so the trap has a vent. This also is handy for any future drain cleaning that is necessary. If you want to go the extra mile, drill a hole in the bottom of the tub and extend the top of the tee up through the floor of the tub. Use a little bit of latex caulk to seal that up.
I don't know why these handy hacks keep proposing such complicated fixes, this plumbing stuff is really easy. Anyone can do it.