Agree with above about reading. My math kid loves to read also.
Self advocate. Start now. Even small things like ordering and picking up the pizza. Talking to teachers for help. Start them doing basic laundry. Teach to cook basic things so helping in the kitchen.
Open up a credit card account that you are on with bank account if you didn’t do it already. Have them sit with the banker to learn how to establish credit. Can do it his like Junior year. Both of my kids never ever needed cosigners for apartments or anything and both graduated the last few years with credit ratings over 820.
Have them pick Ecs that they enjoy doing not to look good on a transcript.
Let them fail. Then help them learn how to succeed.
Unless there are no known issues I like the idea of doing a practice Sat /Act but not for what you might be thinking. We did it in 9th grade ourselves not through the school and picked up some things to work on. It was very obvious for one of my kids. We got the help and quickly turned it around.
Also… Let them be a kid. No one is curing cancer in 9th grade.