From Quora: My Answer to "What are some benefits of taking the SAT in 9th grade, and how do they outweigh the disadvantages?"

The only advantage I can think of is that you’d get practice for taking the PSAT in 10th or 11th grade, and for taking the SAT again as a junior or senior. Unless you got a perfect score, in 9th grade, you’d end up taking it again.


So it doesn’t outweigh the disadvantages - you’d waste your parents’ money on the test fee, especially since you can do practice SATs for free at home (the College Board makes practice tests available for free online). Here’s the link: SAT Practice Tests


A good practice / review book would also be a good investment - roughly $20 for a comprehensive review. You can also check out Khan Academy’s SAT site (just Google it), or you can check out my own YouTube channel’s SAT videos. Here’s the link: John Linneball Tutoring
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You’d be better off doing that, and reading as much as you can about anything, learning how arguments are constructed, and similar things, so you’ll do well on the critical reading and essay parts. You could also practice the English grammar you’ll need to know for the non-essay “writing” section. Acceptable grammar for the SAT is different from common US English grammar, even formal writing grammar. For example, “they” won’t work as a gender-neutral singular pronoun on the SAT, although people use it all the time in everyday speech and writing.