Of course, why didn't he became King Kong and use Ultra Instinct to win the match XDDD in the end we'll see the gorilla pop like a giant freakin cherry once U.I. mode abruptly ends~ Why are his greatest powers also his greatest weakness~?
The reason Goku didn't become an Oozaru is because he doesn't have his tail anymore. It was cut off when he was a kid, cuz back then when he became an Oozaru he would be unstable, so then the tail was cut off. That's all I know about that.