i think you're probably being a little OTT at 9months your DD is still so very young and a lot of the traits of ASD don't show up until later. Could your DD be teething? Perhaps she's 'grinding' because her mouth is sore?
Its only natural that us mums worry far too much about our kiddies..don't stress i'm sure your DD is fine.
I didn't notice DS (who is on the spectrum) grinding his teeth until recently and he's 3, i don't think all teeth grinding means ASD but i could be wrong?
If you're really worried take her to the MCHN..i'm sure they will put your mind at rest