My 6 month old does not roll over yet?

My daughter is 8 months. She didnt start to roll until two weeks ago (7months at the time) and she is still wobbaly (misspelled?) when she sits on her own. My daughter had a birth trauma so we have ECI (early intervention) come in a look at her. The OT (occupational therapist) said to have her at least 90 of her time of the floor, or hard surface. (table while you are with her!!!!!!!!!!!!!!!!!) and immedately after three days my daughter was rolling. it was a big concern of mine and now she cant stop!!!!!! her sitting is getting there. just have him be on the floor with a blankent and ter toys around him and he will want to play so it will force him to move. when you have time get on the floor with him and play. You will have so much fun. Also when you're watching your show (which is normally 30min-1hr) sit on the floor with him, place him in front of you (hi's going to be on the floor sitting inside your legs and your legs should be apart, like if you are stretching. seperate your legs wide enough to where your thighs are hugging his hips waist and just hold by his stomach. get a little basket and fill it with toys and place it in front of him and he will just dig in and throw and of the toys. this will make him want to get the toys from the floor that interest him and wherever they land he will have to use his upper body and balance himself to geet the toys. it will help him strenghten his core. do this 30 mintutes to an hour a day and itll help.