Recoil is a function of energy. When you're talking golf balls the mass is so small compared to the cannon that unless the velocity is extremely great the recoil is minimal.
Let me put it in perspective. The hand held golf-ball mortar shown with several of us firing it on this board, weighs about 6 pounds (42,000 grains). The golf ball weighs 45.6 grams which is about 704 grains.
The kick is less than a .38 special. (That's firing it with enough black powder to go 150 or so yards.
On the other hand, if you want to get it up to 4000 fps you might need soemthing extra. (Can you see the golfball hooking or slicing at 4000fps?).