Gauges aren't accurate (apparently although as far as I'm aware no one had ever proven this) but they are good for consistency
I pump mine so that it is easy to bend it against the sand but it pops back to shape.
All kites are different though, some need high pressure yet some work well at lower pressures.
Nemesis as I remember have very small leading edges so need to be pumped rock hard (they are designed to be pumped hard). Also in high winds it can be advantageous to pump the kite harder to hold its shape in the gusts. I would start at a lower pressure and then work up, try to use the least pressure as possible to prolong the life of the kite.
But IMO a kite that needs 9+psi is generally not a good design!