Oh H.! Can I relate! My daughter is now 15 months, and pretty active. Around 9 months, I had such a hard time changing her diapers because she would not stay still, she would roll over, crawl away, you name it. Yes, she would get away with poop on her butt, it was crazy! There were times when it would take 15 minutes to get a diaper on her, it was ridiculous. I was frustrated and she was too!
She loved to stand and play with things on the couch, or the ottomon in her bedroom. So I tried to put a regular diaper on her standing up...OH BOY! However, my saving grace for this period of time was Pampers Easy Ups, they are meant as a training pant, so they don't hold a ton, but I was happy to change her more often to give up this battle. Nightime, I had my husband help so I could get a regular nightime diaper on, but during the day, I would try once to get a diaper on her, if I couldn't get it on on the first or second try, then I just let her stand and play and I used an Easy Up.
We have just recently gotten back to being able to use regular diapers, but I still have Easy ups on hand, because to me, it is not worth the battle to fight her for a diaper change.
Good luck! :)