Latin is one of the most powerful languages for building vocabulary decoding skills for the SAT. It doesn't give us anything like all our SAT-type words, and learning which sound combinations are likely for Latin roots and which ones suggest other languages that have contributed many technical words can be an immensely empowering activity on its own, but if go go through the dictionary and count, the largest number of words will be Latinate. They will also LOOK a lot like Latin, because they didn't evolve from it "naturally". They were invented by bilingual authors, usually in the Renaissance and after, who were relying on bilingual readers to understand the new words they were getting away with making up.
That said, there is one element of SAT prep that goes beyond learning roots and prefixes which should never be ignored, most especially for students with a significant amount of time before the last date they must take the test, and that is simply reading. In English. As much as possible. The SAT is designed so that the absolute highest reading scores are meant to identify kids who have been voracious readers all their lives.
So if I help you with your SAT, expect to do a lot of Latin-derived stuff in actual sessions, but in between (especially if you have a good amount of time to work with before you take the test), expect to read. There is sure to be text in both fiction and nonfiction that tracks with your interests, though finding some kind of hook in a text that frankly bores you is a central skill too. But read, read, read. Get out of your comfort zone. Be exposed to as much text written for college/adult readers as possible. It's a big world out there with few gatekeepers and funding for trained librarians decreasing, but there is also an incredible amount of opportunity.