I also have a 9-month old who refuses to finish a bottle these days. I always make a 4 oz bottle for each of his 3 meals a day (he is eating stage 3 and some table/finger food), but he never wants to finish his bottle. My son has a pretty healthy appetite, so I always try to give him the bottle first. He always knows that food is coming next, and gets impatient and pushes the bottle away after a couple of ounces. He takes a huge before bed bottle, so I always hope that makes up for the poor interest during day.
Like you, it used to worry me like crazy that he wasn't getting enough liquids, but he has plenty of wet diapers and he is certainly not constipated. He is so healthy and happy, I just don't let it worry me anymore. Sometimes I will give him water or formula out of his sippy cup, and he is a little more responsive to that- he is getting very interested in cups lately. All in all, I would say that he gets about 16-20 oz per day, which seems to suit him just fine.
I am sure she is getting plenty. If not, she would let you know!! As long as she has plenty of wet diapers and is healthy and happy, don't let it worry you. You may want to mention it to the pediatrician at her 9-mo visit if you are still concerned at that time.