you will find a big spread in tyre pressures depending on things like rider weight, tyres, track size, track temp, ect ect ect
Like I know of some guys running as low as 10 and others as high as 30
I used to run the 90/90-12 kendas and they like mid to high 20's but now run Dunlop TT92's and they like 20 flat.
Rider preference plays a fair part tho and I think if you run to low you will pinch the tube to easily ( much below 20 and you WILL NEED rimlocks )
btw this could have probably just been added to your kenda tyres thread considering I guess your trying to work out what to run in your kendas.