Hi
If I start for CAT 2021 from today and if I devote 8-10 hrs per day, can I achieve 90+ percentile

Hi
The time is relatively less but if you are ready to put in 8 to 10 hours daily from now , you can achieve more than 90 percentile in actual CAT .
CAT is an exam in which strategy and planning plays a major role and compliments your preparation . If you are able to strategize well , identify your strengths and approach your preparation in a planned and strategic manner you will be able to score more than 90 percentile in CAT .Try to cover basics as quickly as you can and jump to sectionals and mocks within few days as appearing for tests is the most important thing in CAT preparation.