Hello,
Whether the admission form for class 9 or 11 is still available depends on your school and board. Some schools close admissions after the official deadline, but many allow late admission for a short period if seats are available. You should immediately contact your school office or the admission department and ask if admission forms are still being accepted. They will tell you the last date and what documents you need. If the board or school has closed online forms, you may still be able to apply directly at the school.
I hope this helps you.