Yes you can eat kangaroo testicles. It's meat.
There are very few parts of very few animals that you can't eat.
I've eaten bat, squirrell, cat (unknowingly and not by choice I must add) and seagull.
foxyno1 - Thailand does NOT have any kangaroos, so I find it odd they would be on a menu there.
I've been to Thailand and China and never seen them on a menu.