Can I use this in my RV?
Yes, as long as you have an OBDII connector. If not, you can use an OBDII power adapter (either USB or 12V Cigarette plug) to power it on.

Do I need to buy other parts?
No, unless you don't have an OBDII connector in your RV

Do they run a credit check to put in my name? How does that work?
Yes, a soft credit check is required. It would be similar to activating a new sim card or data plan