First off, what course are you applying to? You have to make sure that your combination of SAT Subject Tests/APs will satisfy the specific subject requirements for your chosen course.

If you’ve achieved at least a 1470/1600 minimum on the SAT, then we would look for a combination of 700+ on the SAT Subject Tests in addition to a 5 on your lone AP test. We need to see a combination of 3 subjects between the SAT Subject Tests + AP tests; you currently only have 2: Math and Physics. This means you have to take a 3rd Subject Test in order to fulfill the minimum entry requirements to be considered. On top of that, strong performance in your current AP classes is also important for your candidacy.

Predictions for IB and A-level courses are expected and routine for school teachers and administrators, but predicting AP scores is not extremely common. Will someone at your school be willing to predict your current AP scores for as your referee?

I am applying to the PPE program at the University of Oxford. When I emailed the PPE department about my qualifications, they said that I could apply provided that I meet the scores (or predicted to meet the scores). Also, for Oxford Applications, do you need to submit your SAT Subject scores when submitting the UCAS application?

It’s usually not necessary for you to submit the scores when applying through UCAS, but if you are accepted you will need to send the score officially, provided you are admitted on the basis of having achieved those scores!