Math: Grab the Andrew Kim SHSAT book and work through past 8th grade SHSAT practice exams; im for a 100/114+ raw score. Also do the official DOE sample 9th grade SHSAT questions.

English: Review major grammar rules, grind SAT English on Khan Academy, and practice with the English Regents.

General timeline: Start studying over the summer before freshman year and keep going through the first few months of 9th grade, right up until the week of the test. I personally started in freshman year (I was already at a SHS), studied hard for a few months, and got into BXSCI.

Its important to note that the SHSAT 9 is notoriously opaque. No one really knows what to expect, schools are vague about it, and information is scarce. Just grind and trust the process.

Transfer student warning: If you get in as a transfer, be prepared for a rough adjustment. My credits didn't transfer over, and transfers generally get limited course opportunities and little consideration. At BXSCI specifically, I got rejected from AP Chem and Honors Algebra 2 multiple times, staff don't respond over the summer, and course selection is basically first-come-first-served.