In my experience, yes, it is not unusual. I honestly think 9 mo is about the beginning age most kids can start becoming proficient with the use of a sippy. I remember my pediatrician saying that even though lots of sippy's claim to be usable from 6 mo plus, most kids are using it as a plaything only until about 9/10 mo. Of course, every kid is different.
I would say just continue to use it. Perhaps experiment with sippy cups to see which one she likes best- hard spout, soft spout, straw (although she is probably a little young for that at this age).
Try not to stress about it too much. Consider the bottle/breast to be the way she gets liquids and the sippy just something for her to explore at this point. She will get the hand of it.....
