nap time routine?

My lo is 9 weeks old and I don't try to put him on a schedule. I exclusively pump. But I'm wondering when I should start a routine. His nap times are all over the place usually. Sometimes he naps for 2 hours and sometimes it's only for 30 minutes. Yesterday he was eating 2 ounces like every hour and a half.. when usually he goes 2-3 hours and eats 3-4ounces. I wonder if the cluster feeding is normal at this age? And maybe I should start a routine? He has been sleeping great at night tho.. he gets a bath only 2-3 times a week. But I'll feed and pump and then change him, swaddle, read a book, and then rock him to sleep and once he's drowsy I put him in his crib and he falls asleep on his own. He has been waking up between 1-2:30 and then again around 5:30 the past two nights so I've been getting a lot of sleep.