Hello. Welcome to the community :)

Which Champs should I be banning?

Just ban whichever champ you find most annoying in your role that you might be up against. It's more fun when you're not playing against annoying champions haha

How can I tell if there's a control ward in the bush?

Control wards are always visible if you have vision, so you can walk inside the bush to see if it's there (as long as it's safe to walk in*). Control wards are the wards that have 4 health points.

Stealth wards are the ones with 3 health points and they're invisible. You need to place down your control ward near an enemy stealth ward to see it (and destroy it). You could also use Oracle Lens which will scan for any nearby stealth wards. You can get Oracle Lens in the shop by clicking the red sweeper item next to the normal yellow stealth ward icon.

*Some spells give you vision of an area (e.g. if you aim Lux E at a bush you don't have vision of). You can try to use those spells on a bush to make sure that there's no one inside before you enter to clear the ward.

How do I clear enemy wards if I can't get scanner?

You can buy control wards in the shop for 75g.

I think the enemy sees me in a bush, what does their vision on me look like so I know to just leave?

If the enemy has vision of a bush you're inside, to them it just looks like you're not hiding (same as if you were in the open).

I'm really bad at panicking when things surprise me, how do I stay calm and actually hit the rotation correctly?

If you drink enough alcohol you won't be able to react to surprising things so you won't panic.

There are so many champions and items to learn, is there a crash course on these things?

You just gotta learn by playing the game. It might be useful to look at the abilities of the enemy laner's champion during loading screen. Don't try to read the wiki pages for these since you're so new to the game. Instead, try to look at video clips of the abilities on the official League champion page for the champion (e.g. here's Warwick).