If your tree is a smaller 2 foot tall grafted tree, I wouldn’t immediately up pot it to a very big pot. It’s best to gradually step up the pot size. Select the next pot size up and plant it in that. Something an inch or two wider and taller would be perfect. Sapodillas aren’t too picky about the soil as long as it’s good draining.
As for potting soil, if your looking for something off the shelf, a 50/50 mixture of Fox Farm and Happy Frog works excellent. You can easily add your own amendments to a cheaper potting mix but this mix has plenty of all the good stuff to support a great canopy and root development.
Simon