I am being charged $9.99 a month, and I don't know what that is for??

This is primarily a user-to-user support forum; other Apple users like you. We don't have access to information about charges to your account. See each of the steps in the following instructions. They include information on contacting Apple Support if the other steps don't help: If you see 'apple.com/bill' on your billing statement - Apple Support

I have Apple charge for $9.99 on Sept. 9 and would like to know what for. I don’t recall purchasing anything for that amount or date.

Please read my previous post -- the one above that you replied to.