Without having background on you and your prior results in school. I would say to an average student to go at the rate you are meant to be on and simply continue class 9. However if you excel in the past and know that you are better then those in your class, I see no reason as to why you couldn’t proceed to class 11. The only problem I would see is that if you skip classes you will miss out on being taught some basic formula that you will be expected to know going forward.