Last year one of my daughters went through this recruiting process and at an IVY school you have no commitment without having taken the ACT or SAT and scoring rather high. While the coach might be telling you he wants you (and I’m sure he does) he still needs to take all your academic information, including the SAT/ACT scores to the admissions office and get an approval from them.
Also, if you fall below that IVY index, the coach will have to recruit someone with a higher IVY index score than you because he needs to maintain an index score of 200 for your recruiting class. My suggestion is to do the best on the ACT/SAT that you can.
Then if you end up being recruited you will get a “likely letter”. It’s rather scary because it doesn’t say they will definitely take you, but rather that if everything on the application looks okay we will probably say yes.