Feeding Schedule?

So my son is 2 months today... He's got his 2 month shots tomorrow. I'm going to ask the pediatrician this question when I get there but I thought I'd get some opinions here before I go in!

My son was 3 weeks early and only weighed 5 lbs 15 oz at birth. At an appointment last week, he was up to 9 lbs 13 oz. My husband thinks he's still too small and wants to continue feeding him every 3 hours regardless {namely overnight} but I think he's doing just fine and can sleep longer as long as he's not crying. Should I be feeding him on a strict schedule or should I let him sleep? I think he's growing just fine but he's still in the 4th percentile.