9-5er

A person who sticks to a 9-5 job.

A person involved in a mundane job.

Guy 1: Hey, I listened to your rendition of Red Hot Chili Peppers' Californication
Guy 2: How was it?
Guy 1: It was amazing!! But, that's besides the point! I don't understand why you are a 9-5er when you can clearly be the next Anthony Kiedis!