Solved
What do we send with her Federal Taxes as far as the W-9?
If you are filing the return by mail and need the Federal copy of the W-2, it is available online through the myPay website at https://mypay.dfas.mil/. Your child will have to create an account and either download and send the form to you, or give you the user ID and Password.
I've attached sample screenshots from the website. My "menu" is a little different because I'm a retiree.
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.