9 month old feeding advice

Morgan

My son is 9 months old. He wakes up 3-4 times in the middle of the night JUST to eat. We go through so much formula just at night time. When he was in the NICU, for 3 weeks, they woke him up every three hours to feed him and he must have taken that routine home because ever since he came home he woke up every 2-3 hours. I need advice on how to break this habit because we can’t keep going through this much formula! TIA!