National has vans in short-and long-wheelbase configs, broken down as following:

- OVAR: 12 seats, short wheelbase. This is the one you want with 9 people (just stow any bags not fitting in the cargo area on the unused last row of seats ).
- RVAR: 12 seats, long wheelbase. Cavernous cargo capacity, but more cumbersome to drive and park.
- FVAR: 15 seats, short wheelbase. There's almost no cargo capacity behind the last row of seats, but you have two rows of unused seating to throw bags on
- UVAR: 15 seats, long wheelbase.

The three times at LAX and one time at DFW where I have rented a van from them they had both length options available and I could pick whatever I wanted. The shorter versions also had a lower roof than the longer ones, which is quieter and will give you better highway fuel economy (there's more than enough headroom either way)