There is a new requirement for 2017 that requires a Federal EIN in order to claim the American Opportunity Credit. Without this number, you will not be able to claim the AOC but could still be eligible for other educational benefits such as the Lifetime Learning Credit or Tuition and Fees Deduction.
See page 2 of IRS Publication 970 under What's New -
Educational institution's EIN required. To claim the American opportunity credit, you must provide the educational institution's employer identification number (EIN) on your Form 8863. You should be able to obtain this information from Form 1098-T or the educational institution. See chapter 2.