Is it ok for an 8 month old to sleep on his tummy if he cant roll over yet?

[2point4kids]

DS2 is nearly 9 months. He turns from his back to his tummy when half asleep and ends up sleeping on his tummy quite often.
He cant roll back over though, so when he wakes up he yells for me to rescue him quite loudly!

I assume its safe at his age to let him sleep however he wants to, including on his tummy. But is it a worry that he cant roll over??
He can obviously lift his head well.

DS is 6 months and has been rolling onto his front in bed for weeks and weeks. I'm not about to wake him to put him back on his back, he sleeps poorly enough as it is!

xx

So long as he can lift his head, he'll be fine.