should i be concerned that my 9 month old wont roll tummy to back?

There isn't anything wrong with her. If she CAN roll but doesn't want to that's fine. My son can roll but doesn't very often. He'd rather sit or stand and has no interest in crawling.

If you want her to improve with this you will have to insist on more tummy time and work on it. Although, like most things with babies the more you try to force it the more unwilling she will be. If you make it a power struggle she will win! I would suggest that if she wakes in the night that you go in and roll her back immediately. Letting her get upset won't help either. You could try to make a lesson out of it at that time though by showing her what to do. Roll her back over by raising up the arm of the side she has to roll over and let her move her legs herself. Maybe even celebrate with a little "yay, you did it!" and leave her to sleep. Also, when you have tummy time you can encourage her to move more by putting her on a big blanket and placing things she usually cannot have - the remote, mommy's cell, etc - all around her just out of reach. Keep an eye on her if she gets to these things but give her a good reason to get moving!

That seems a little unusual, especially if she has the strength to pull herself into a standing position. Refusing to crawl can be normal (some babies skip straight to walking, especially if you have a non-carpet floor). I don't think she's being lazy. Take her to the doctor for an evaluation, and tell them your concern.

Sounds to me that your baby needs alot more tummy time. Even if she cried and screams she need more tummy time. Talk to her dr and see what the dr has to say about it too. Every child is different so it is best to talk to the dr about things because kids learn at different rates. My son was walking at 10 months and it took my daughter til she turned 1. However there could be something wrong and like I said you need to talk to her dr.

Id say Mix It Up. Make sure she has tummy time, back time, sitting time (bumbo), and standing time( u holding her in standing position). Sometimes the variety can help them pick up on less developed motor skills.