“Hit 'em straight!”
Or as others have said, “Have a good round.”
What’s wrong with just “Good luck”?
Nothing. OP was looking for something more sport specific, that’s all.
Almost any quote from Caddyshack will get you on their good side.
I usually use “Bye! Have fun storming the castle!” as my all-purpose wishing someone off remark, but the intersection between golfers and Princess Bride fans is probably not all that big.
I’m actually more interested in what you’d say to someone heading off to read Walden… somehow ‘storming the castle’ doesn’t fit, here.
I’d probably just say “Have fun!”
As others have said, “round,” not “game.”
Nooooonan.
“Cinderella boy!”
"Oh Mrs. Crane, you’re a little monkey woman. Yeah, you’re lean, mean, and I bet you’re not too far in between are ya. How’d you like to wrap your spikes around my… "
Strangers in the night… exchanging clothing…
“Hit them Long and Straight”
“Play Well”
From Caddyshack
“Your honor, your honor”
“FORE!..I should have yelled TWO”