I think a bolt 9mm would be a lot of fun too! Especially if it were fed from a small detachable magazine.
I recently picked up a Mossberg MVP predator rifle. Takes AR-15 magazines. I have to admit that shooting the .223 out of a bolt action has been one of the most pleasurable, comfortable, and and all around satisfying bolt action experiences of my life.
With prices on ammo right now being around 20 cents a shot for 9mm and 30 cents a shot for 223 it's not too bad.
If you decide to get a .223 bolt action, I'm sure you'll be glad you did. They work well for certain types of hunting, accurate shooting from short to longer ranges, and are a bunch of fun for low recoil casual shooting . A 9mm would be a lot of fun though and if something were readily available, I'm sure i'd be on board. Especially if it came with iron sights.