Hello,

First of all in order to appear for UPSC, you need to attain 21 years age and pass graduation in any discipline from a recognized university, you can apply even in the final year, now honestly speaking there is no such restriction about belonging to any particular stream for UPSC, the thing is to appear for this exam with or without back-up, there are many aspirants coming from medical, engineering, CA background who qualify this exam, so it wouldn't be fair to say that only people from humanities have higher success ratio, it depends on your career goals to a large extent, having a back up plan helps in case you're not 100% sure about pursuing only UPSC, if you're wholly and solely focused on it then you should choose humanities stream courses which can be anything like graduation in political science, public administration, geography, economics to name a few. So, think about all these things and then take decision accordingly, right now you're only in ninth standard, and there's lot of time left for you to appear in UPSC.