Gstr-9a - purchase from composition dealer

Composition scheme biz need not file purchase details while filing GST quarterly returns .....so it is mandatory to file purchase detail in GSTR 9A ?

Yes, purchase details needs to be given in GSTR-9A.

As of now there is no announcement from the government but from the format of GSTR-9A it seems mandatory.

but problem is that in GSTR 4A Purchase shown by our suppliers is very less than our actual purchase, Now which purchase I should show in GSTR 9A ....Auto populated Purchase or our Real Purchase?

Yes this is problem is most cases. It is better to show real purchase.

But it may happen that some of my suppliers didn't show my purchase in their GSTR 1, and if I show that purchase in my GSTR 9A, definitely there will be mismatch and then department will issue notice to me,then headache,reply,personal appearance,gift (?) to AO etc.