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!

Ive read a number of times that under inflation puts your kite at greater risk of blow out than proper pressure. The reason was that when the kite tubes kink during a crash or rough handling there can be sudden increases in pressure, as well as the kite will tend to kink repeatedly at the same spot inducing wear and weakening that particular spot. Proper pressure should prevent the tubes from kinking during normal handling and most crashes. If you can easily kink the leading edge when flipping the kite, it needs more air. Over inflation is also a problem, so no need to go crazy with that pump, but I think there is a happy pressure that is best for both performance, relaunch and longevity.

I tend to go by a combination of the sound when flicked with a finger, and feedback at the pump. I also only fly two kites and have an idea of how many pump strokes it takes to get them to pressure. Getting an idea of this helps with consistency.

No way that your strut should have burst at 9 psi, in my opinion.

It was the bladder I think and not the strut..........and it was a new kite, you should never pump a new kite up to the max straight away, bladder bursts are relatively common on new kites as the bladders aren't always fitted correctly and haven't had the chance to get seated properly, they usually explode into the voids So probably not the pressure, more so just a new kite and you need to be gentle when pumping up a new kite.

Exactly the same when refitting a bladder, always pump up slowly and shake/caress it so it fits properly.

My 2007 GK Sonic did the same when I first got it rode it without end strut inflated still awesome kite