My kids definitely didn't sleep through the night at 8 months. My 2 year old still gets up at least once most nights, and my 5 year old goes through phases when he gets up. Not trying to make you feel depressed, just letting you know that this is normal.
Personally, I sleep so much better when I just bring them into bed with me. My husband and I are very fortunate to have a king size bed, so there's plenty of room. (We were just joking about that last night.)
Our boys always begin the night in their own bed. If they wake in the middle of the night, we don't usually get up, they just know they can come in and join us. That way they get their hugs and reassurance and go back to sleep easily.
We actually co-slept with your boys at that age. We tried to get our oldest to sleep in a crib, but definitely gave up trying to get him to stay there all night when he was around 8 or 9 months. With our second, we didn't even try. Looking back, I'm not entirely sure why we bothered setting up the crib at all. As a newborn he slept in his carseat. When we was too big for that, we began sleeping with us.
If you're open to co-sleeping, I highly recommend it. I think you'll find you do get more sleep. Also, I wouldn't worry too much about him sleeping on his tummy at this age. Sounds like he's perfectly capable of rolling over if he needs too. The risk of sids decreases dramatically when they can roll over on their own.