Multi-user account

Is it possible to provide a client access to only their data that's been collected from their survey and/or form?

If I understood you correctly, you want to provide access to your client only for data that are collected form their forms. You can add them as sub account users of your account and give them permission to view only submission of their form. Inside of this guide you can find out how to share forms with a sub account user: http://www.jotform.com/help/232-How-to-Share-Forms-with-a-Sub-Account-User 

Your client first need to sign up for JotForm by registering for a new account. Then when you share form with them, they will be able to view shared form on their account.

Hope this will help. Let us know if you need further assistance.