im sure that a crystal switching arrangement could be breadboarded up to give the radio different bands of 40 channels.
that is the possible part of what you want to do.
the problem lies in all the tuned circuits down the line from the PLL section.
for different reasons, each of these circuits is built with a specific bandwidth of operation in mind.
yes, they can be broadbanded a bit, but the range of this type of radio is about 2-2.5mhz max.
so, if you want to change the radio to work on 7-9 mhz, yes, it could be done, but you would end up having to change most of the parts in each of the tuned circuits to do it, among many other changes that would have to be made.
anyone who has the knowledge to work out all the math to do such a thing could build their own 7-9mhz transceiver with less headaches.
sorry, its just not gonna happen,
you're not alone though, many have had this same idea,
LC