I scored pretty well on the SAT and I was wondering if it was OK to list the score on my resume. Or would it be pretentious to do so?
What positions are you going for?
If you are going for an SAT tutor position, the high SAT score might be relevant.
If you are going for a software engineering position, you mention of your SAT score will illustrate that you are at worst out of touch with the requirements of the position.
If you don't believe that your resume should be targeted for the type of position that you are going for, then I am the wrong individual to answer your question.
Colleges care about SAT and ACT exams. Some scholarships care about these scores. It may be that a internship for incoming freshman care. Otherwise no, they don't want to see your SAT scores.
One issue you would have if an employer wanted to know your score, is that there is no mechanism to get official scores to anyplace besides colleges and universities.
If you took AP or IB exams for a particular subject and achieved high scores; it may help to mentioned that when applying for an internship to emphasize your skills in that area.
I wouldn't include SAT or ACT scores on a resume. It is Ok to include information that some employers don't want to know, but it is not good to include information that no employer wants to know.