If my daughter is 8 months almost 9 months and knows how to roll over and move can I let her sleep…

yes. usually once they have decent control of their head and can roll on their own its perfectly acceptable to let them :)

my son started sleeping on his stomach way before that and was fine

Yes because she can roll on her own now. I don't let my daughter sleep on her belly only because she has some issues.

she seems to sleep WAY better on her stomach.. because when she sleeps on her back she wants to roll and it wakes her up.. @andiryan93 @nyckolle00 @pixiestix

and her arms don't go wailing up when she has a bad dream.. @andiryan93 @nyckolle00 @pixiestix

let her sleep on her tummy! no harm in it! my son slept on his side from the moment he was born. honestly, i let him sleep on my feather pillow until he was able tp keep himself on his side. hes almost 6 and still sleeps best on his side. lol

As long as she can roll by herself then yes plus baby will sleep the way the want anyway

Yes. All my babies slept on their stomachs from the time they came home til now.....