Do prep schools like Loomis, Deerfield, Exeter Do Math Placement Tests in 9th grade?

Also - Cate told us that they don’t even offer Algebra 1. If you were not taking Algebra 1 in 8th grade, you would have to take it over the summer (or maybe you won’t get in)? I guess it’s because it’s a small school and most take Algebra 1 in 8th?