Help with my cat

Ok, here goes.

My friends say I'm suppose to lock my cat up in my bathroom, where his food/water/litter box is when I'm not home. However, he is 10 to 11 years old and has always had free reign of the house.

Am I really suppose to close him off in the bathroom when I'm at work? They say he will get into things and stuff. Yes, today he threw up on my cleaned up floor but I got it up...