So I called Johnson Nursery who supplied the tree, and they said their trees are already shaped. So anybody else who bought from them and might be wondering- you don't have to cut it back!

And hopefully UGA meant a 30 INCH tree, not a 30 foot tree!!

Yes, Johnson's trees are a bit more mature than most trees you purchase. The man who runs the nursery end of it came to drop off plants at the store I worked at a few years ago. So I was able to ask him a lot of questions. He does the grafting and all the growing and supervises all the pruning (doing most of it himself.). He prunes the trees as if you chose a single yard tree on a grassy lawn. There are many styles of pruning David Wilson nursery in California outlines pruning to a smaller caliper for multiple trees on city lots. Maximizes production so you get get more trees in a yard if that floats your boat.
I'm hoping that Trees Atlanta is going to introduce both fruit tree pruning and fruit tree restoration classes to it's services in the near future.

Haha- it did seem extreme in any case to cut a 30-foot tree down to 24"! And where, I wondered, was UGA finding these mythical fruit trees that grow to 30 feet in one year? Hopefully that was a typo.

The Johnson folks were wonderful- even though I didn't buy the tree directly from them they immediately mailed me literature and seemed very knowledgeable and passionate about their trees.