Can I report players for banning my champions in ranked on purpose?

You seem to have a lot of questions about reporting people "CaN i RePorT mY sUpPoRt FoR PlaYinG brAnD? WhAt AboUt ROaMinG?" The answer to all of these (aside from the roaming one, I understand your confusion) are addressed by Riot

Nope It's not reportable

Yasuo main? Zed main? Teemo main? Yuumi main?

There are 145+ champions, and each person can ban exactly one. And they can pick whatever one they want, and this is not likely to change.

Just banning a champion won't ever get anyone punished, nor should it.

Anyone, including yourself, can ban any champion for any reason they want.

So no, you can't report someone for playing draft pick the way it was designed. Look, we all know it can be frustrating, but pick intent is just that - intent. You don't always get what you hover, and you can change what you're hovering at any time.

Draft pick goes ban phase then pick phase, bottom line.

No its their ban they can ban what ever they want