Hi Kurt, I believe it is incorrect that box 9 being checked will itself disqualify you from being eligible for the AOTC. See question 13 from the AOTC Q&A on IRS.gov shown below:
Q13. If a student was an undergraduate during the first part of the taxable year and became a graduate student that same year, will the student qualify for the American opportunity tax credit?
A. If a student has not completed the first four years of post-secondary education as of the beginning of the taxable year, and has not claimed the Hope scholarship credit and/or the American opportunity tax credit for more than four taxable years, the student can claim the American opportunity tax credit for qualified expenses paid during the entire taxable year.
For example, my wife completed her undergrad in 3 years and is finishing up her masters this May. So at the beginning of 2019 she was still an undergrad (had not completed the first four years of post-secondary education), May 2019 she graduated with her Bachelors, and August 2019 she started her graduate degree. Her 2019 1098-T has her total tuition expenses(some from undergrad and some from grad) in box 1 and has box 9 checked.
