I sold my leased VW to Carvana a few months ago. The plates go with the car. As stated by @KD6-3.7 you need to fill out the DMV release form within 5 days of the sale: https://www.dmv.ca.gov/portal/dmv/detail/online/nrl/welcome
Call VW Credit a few days after pickup to verify that the lease is no longer in your name. They messed up on my transfer by short-paying the buyout amount (VW gives a buyout amount for the lesee and a higher one for dealers). I was not confident that Carvana fully knew what they were doing with VW Credit since they stumbled their way through the transaction. Hopefully they are better now. See my post: