what if first pick ban only for himself, can I report him?

Is there a report option "didn't ban the champions I told him to ban"? No. This should answer your question.

Also, relevant: There is no report option for "picked a non-meta champ". There is no report option for "used a build that doesn't match what I read on mobafire". There is no report option for "support didn't buy a sightstone and asked me to actually use my trinket". There is no report option for "jungler didn't camp my lane and give me every single buff I wanted".

No. Why would u report him for that?

First ban should always be Vayne or Volibear, depending on team comp. Its also very helpful if you listen to anyone going Tank and instantly ban Vayne in order to give them more mid-game survivability

ahahahahaaha this board is the best