Another vote for NOT prepping.
If I recall correctly, DD2 took those tests in May, so you should still be in the swing of what you are learning. As it happened, school stopped for DD2 last March because of covid weirdness, so she felt very rusty. She ended up testing into the typical 9th grade math track (Andover has a slightly lower math for kids who might need to “catch up a bit” – by BS standards I mean – and then regular math, and then of course the advanced for the serious math whizzes.). DD2 was taking 10th grade honors math at the high school in 8th grade, so 2 years “advanced” for our town, but right in line for the “regular” 9th grade math at BS. And it was PLENTY hard! I am super glad she didn’t prep! (Oh, and first two days, she called home and worried that the class wouldn’t be hard enough. Days 3 and 4: “oh maybe it will be fine actually.” Day 5+ “holy cow mom, can I FaceTime you with some questions?”). (Me: googling how to find the distance between a point and a parabola…yikes)
Foreign Language – she tested into French 2. As it happened, my DD1, who is a year older, took French 2 at the local community college this fall. Well funnily enough, both the college class and Andover were using the same text and software program, same level, for parts of their classes, so they could swap stories about different assignments. But also: French 2 at BS was super challenging!