composition scheme

you should first understand the difference between the ---
*goods on which gst is not leviable
*exempted goods and
*0 rated goods....
as far as your question is about composition scheme, the answer is yes, person selling exempted goods can opt for composition scheme provided other conditions are satisfied........
answer of your second question is that, section 9 of cgst decides the goods which are leviable to gst.....means on which CG has power to levy gst.....the items which kept out from gst by this section are the items on which gst cannot be levied....for example

on alcoholic liquer for human consumption, petrolium crude etc gst is not leviable..hence if one sales them than he can not opt for composition scheme...

 

Thank u Sir