Can I add books required for college classes that were not purchased at the school bookstore?

Yes. For the American Opportunity Credit (AOC), books are an allowable expenses, regardless of where purchased.

I'm of the opinion that tools would also be "required course materials".  In TT, enter as books not purchased from the school

You can use required textbooks not purchased at the campus bookstore as a qualified educational expense for the American Opportunity Credit only.  You cannot add the purchase of tools for the HVAC installation.

After entering the 1098-T, you are able to add additional expenses which are not listed on the 1098-T by selecting "Expenses and Scholarships (Form 1098-T)" then "Other Education Expenses (for all schools)"  in the Education Section under Deductions & Credits