All the details are here.
https://www.montgomeryschoolsmd.org/siteassets/schools/high-schools/r-w/rmhs/ib/2023-2024-ib-course-handbook.pdf
Basically for 9th they take magnet courses in English and Biology and usually magnet Algebra 2. Also most do AP Government and they all continue their foreign language. It’s common to take PE and either fine arts or technology to get requirements out of the way.