9 month old baby keeps rolling to his tummy while sleeping… how to stop this!!?

My 9 month old son recently started rolling over on his stomach while in his sleep. I fear he might affect him in the worst way it could.. SIDS..

Anyone have ideas how to prevent him??

I can’t stay awake forever trying to watch him and flipping him every few minutes..

Any suggestions welcome..

UPDATE

unsure if I was maybe unclear. His crib is safe as safe as it could be, I understand his flipping is part of developing, but it becomes unsafe if his face is turned directly to his mattress..

Everyone keeps saying this is ok.. would you let your baby sleep like this?

UPDATE:

Thank you @blessedmom

She gave me an idea

She co sleeps with her baby!! I thought bingo!! He still fits in his bassinet, it’s a big bassinet why not have him sleep there next to me like he did when he was a newborn so I can flip him quickly. So that’s what I will do since I really can’t prevent the flipping.. maybe I’ll even catch some zzz’s