Reserve GR9s for fun and games?
No chance. It would mean effectively keeping all of the engineering and infrastructure costs with the savings being only on the number of hours flown. And with all due respect to the Bona-Mates out there, how many hours are you going to need to be safe, let alone combat ready?
Not going to happen.
... Since Lusty has been chosen over Ocean for the axe then there would be little point as it wouldn't get to sea