Is there an official way to send my IB predicted grades to a?
I believe the statement you quote refers to SAT/ACT/AP/ TOEFL. Test scores are self-reported on MIT application and some schools include them in the students transcripts, but MIT also requires the official score reports to be sent directly by the test companies. Predicted grades should be included into a letter/report submitted on your behalf by your school guidance counselor or other school official.