How many hours should I study in class 9 and sleep?

You should sleep for about 6-8 hours. Which is normal course of time for proper sleep. Spend the remaining time in the practice with complete focus on the only topic you are doing will let you earn more knowledge in less time. 

Get mentorship for something you are not able to understand. It wi help you with everything you need to know. 

after coming from school you should rest for 30 mins then study atleast 3 hours for homework/revise what teachers taught today then in evening go for outdor play for 1 hour regularly and after coming home at take dinner or study for 2 hours atleast before sleep where you revise concepts and solve exercises etc. then if time permit then study 30 min and 30 min physical exercise in morning for better health...because a healthy body is necessary for healthy mind...in short 5 hours of study with 1.30 hours of outdoor games and 30 min of exercise if best for you.

after coming from school you should rest for 30 mins then study atleast 3 hours for homework/revise what teachers taught today then in evening go for outdor play for 1 hour regularly and after coming home at take dinner or study for 2 hours atleast before sleep (7-8 hours) where you revise concepts and solve exercises etc. then if time permit then study 30 min and 30 min physical exercise in morning for better health...because a healthy body is necessary for healthy mind...in short 5 hours of study with 1.30 hours of outdoor games and 30 min of exercise and 7-8 hours of sleep is best for you...one more thing dont watch TV before sleeping time you will get top score in your exams...regular revision and homework completition with weekly revision is the key of success...apply 3 D's in life...Dream....Determination....Discipline 

*I believe in quality and not quantity. It isn’t about how many hours you study, it’s about the benefit you obtain .

*Don’t compare your routine with others, make your own, take your own time.

*Take breaks inbetween, when you feel you are losing you concentration take a small break and refresh yourself and then continue again.

*Keep your mind relaxed, always try to keep yourself caln, you might be stressed with other stuffs in life but relax and in the long run you will be able to concentrate inspite of all those.

*Sleep, it varies from person to person, but on average try to take atleast 7 hours of sleep at night and if possible a small nap in afternoon, this will keep you fresh throughout the day.

*And don’t forget about diet, have a healthy diet. It’s important as well.