i was charged 9.99 by itunes but i dont know what its for

You can use the following to determine what a charge is for and to report a problem: Get help with an item purchased from the App Store, iTunes Store, or iBooks Store - Apple Support

If the only indication of the charge is from an email or text, be aware that it may be a phishing attempt to get you to log in to a site that appears to be Apple and divulge your password or credit card information. Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

Also see: If you see 'itunes.com/bill' or an unfamiliar charge on your bank, credit card, or debit statement - Apple Support