Following cause my 11-month-old is the same and I also try ways to communicate to him to be a little gentler.
The pediatrician told me that when he hits or bites, to put him down if you’re holding him and do not give attention to that behavior.
It sounds like your little one has a lot of energy! Since he’s already showing some understanding with the cat, that’s a good sign. When he starts to smack, gently take his hand and show him how to be gentle. Use a soft voice and say something like, “Gentle hands.” If he’s getting a bit too wild, try to redirect his energy to a toy or activity that he can smack without causing any harm. When he does something gentle, praise him! Let him know he’s being a good boy when he uses gentle hands. Every time he hits, respond the same way. Say “No hitting, that hurts,” and then guide him to a gentle way to wake you up, like a light tap or a cuddle. At his age, they’re just exploring boundaries, so it’s about teaching him in a way he can understand.