Sleep advice for 9 month old

So my baby has slept through the night before. I would say it's a 40% chance if he will sleep 8 hours straight. But lately it's seemed less and less. He wakes up every 6 hours and the only way he'll go back to sleep is if I feed him. I've been trying to cut the amount of oz back but I'm worried because in a few months no more formula so I don't know what I'm going to feed him if he wakes up. He has a solid bed time routine and I feed him well before bed. I put him down around 8:30-9:00. But even if he sleeps 8 hours he's still getting up at 4-5. I've had people tell me sleep is developmental but from what I've researched there isn't any reason why he shouldn't be able to sleep 10 hours..

Please give advice...I feel like a failure...