Will this clear my O2 sensor code?

If your code is pointing to the rear right position, yes — this sensor will resolve it. Clear your codes after installation and verify the fault does not return on the next drive cycle.

Do I need to disconnect the battery before installing this?

Disconnecting the battery is not required, but it's good practice to kill the ignition and let the engine cool. The sensor sits in the exhaust — wait at least 30 minutes after shutdown before touching it.

Can I reuse the old sensor or sensor socket?

Sensors are single-use — replace the entire unit. The threaded bung in your exhaust can be reused if it's not damaged. If it's stripped or cracked, you'll need a new bung or bungs kit before this sensor goes in.