I am from India and travelling to Germany on a Schengen visa. On my way back to Mumbai from Munich, I have a layover of 9 hrs in Zurich. Can I travel in Zurich on the same documents or I need anything more?
Switzerland – while not part of the European Union – belongs to the Schengen area so you don't need anything else than a Schengen visa. You won't even leave the Schengen area (or, in all likelihood, see any border guard) before leaving Zurich.
You can, if your visa is valid for the Schengen zone and not just for Germany (it will say on the top of the visa).
If you have such a visa, you are free to travel within the Schengen zone (of which Switzerland is a member). Upon exit from Switzerland, your passport will be stamped as you will be leaving the Schengen area.