2-strokes love VP C12 (or any other leaded, higher-octane fuel). Unless you're running very high compression and/or aggressive ignition timing, straight C12 might be overkill. A 50/50 mix with pump fuel is probably "good enough".
You should probably be asking what the minimum octane rating should be if your looking for the most power.
That stock motor should be just fine on straight pump 93, but cutting it with some 100LL if you have easy access to it wouldn't be a bad thing. Premix ratio is subjective, but I would run more oil in high revving 85 zipping around a kart track.
To answer your question, yes, you can run 95 or 100LL. However, if the engine is stock your best bet is ethanol free 93 octane, and then learning to read the spark plug and jet accordingly. Without getting oxygenated fuel, simply going to a higher octane number is more likely to decrease performance than increase performance, while learning to jet appropriately on whatever octane Kawasaki recommends will get you noticeable gains for free. Chances are, if you haven't changed your main jet already, it is way richer than you need, and costing you power. I ran 93 pump gas in my CR85 road racer for years with no problems. I didn't switch to 110 until I had it bored out, ported, and had the head modified for higher compression, which then required me to run higher octane. The power comes from the mods that require higher octane, not the octane number.
also pay attention to the flash point of the premix oil you use and the throttle openings. Lots of WFO requires a higher flashpoint vs part throttle openings.
