There is a good chance you can take Commerce in 11th grade even if you didn't study Maths in 9th and 10th, as long as you have approval for a substitute subject due to being specially abled.

While specific requirements might vary slightly depending on the board or college, Commerce in 11th grade typically requires students to have studied Mathematics in 9th and 10th. This is because Maths forms a foundation for some Commerce subjects like Statistics and Accountancy.

since you have special needs and approval to replace Maths with another subject, this changes things. The fact that you have this official approval due to being specially abled should supersede the general Maths requirement for Commerce.

I hope it helps!