Hello friend, it`s good that you are interested in IIT and you know your weak point and want to improve it. As your are in std 9th you have time to improve yourself, for that firstly you need to be thorough with your basic syllabus and if you wish to prepare for JEE Mains, you can prepare for it in your holidays like every Sunday on a daily basis or whenever you are free and feel like you have nothing to do but the thing is it should be done daily. This will make your preparation constant and won`t harm your personal studies or school exams.
