Could be a couple of things. I would start teaching her some sign language such as eat, milk, more, things that may make your life easier ... please, etc. Also, at 9 months my son was teething like crazy and it was torture. So maybe a little tylenol before bed so that she can sleep better. My son just turned 23 months and WAS the perfect child. Now he is whiny, crying, and throwing some temper tantrums. The terrible two's have arrived and I am just hoping to nip this in the bud before it gets worse. I am hoping he is over the "MINE" stage before this summer when he will be around a lot of kids. But I think if she knows that she can communicate with you then she won't be as frustrated. Also make sure she is eating enough, she may be going through a growth spurt. This won't last forever. Just let her know that she can't act that way. I think once she can crawl she will be better. But always ask the pediatrician for any advice and let them know your concerns, too. Good luck and best wishes.