After 9.20 i feel two things. Garen is overpowered but quite easy to balance. But I am not his player, can't really tell much. Don't worry about him. He will be adjusted so don't panic.
Shaco's clear will be addressed as well in the 9.21. He will need a buff then since his winrate already fell to 51% but that is how balancing works. Next patch Shaco will be 50-49% winrate, which for a onetrick champion is low. After this nerf, i feel like his survivalability should be enhanced, not damage, to avoid him being too oneshotty again. He is doing enough dmg as it is.