I use to think back when I was younger that "premium" gas was better quality and therefore better for your engine, power, etc., but now I believe that the only gain you will get from it is less chance of preignition. This is why higher compression engines normally need it. I say normally because if you keep up with some of the modern engine building techniques and components used in hot rodding(such as high-tech coatings on pitons and cumbustion chambers), people are able to run much higher compressions than ever before on pump gas when a similar build use to require race gas. High compression is not a requirement to run straight alcohol. I use to build quite a lot of alcohol kart engines as a hobby( flat head 5hp Briggs) and building one of them with higher compression is a relative term. They are never no where as high as most modern-type overhead valve engines. And there is a very noticable power gain in them simply by goin from gas to alcohol. Yes, engine cooling is a performance booster as well. Those little Briggs run 400-500 degree head temps, and the carb will be cool to the touch and sweating like a pig from the cooling effect of the alcohol. Look at the difference in the size of the jets needed. You aren't flowing anymore air, but the fuel flow has to increase dramatically. That fuel fills volume, and the increase in the volume that the fuel fills decreases the volume that the air can be compressed in to. Fuel droplets, and the like, are still liquid, and therefore are non-compressable. I cant guarentee it because I'm definitely not a 2-stroke expert(or any other kind, lol), but I would bet if you change nothing else on your motor but the jetting needed for alcohol and ran it on thatt, you would notice a power gain.
If you suspect that your engine is "pinging", go up in octane. Otherwise, I dont see where higher octane is gonna help you. Also, 10% alcohol in gas will decrease the average cars milage by 12%. We have a couple of stations around here that have signs stating that theres no alcohol in their gas. I buy there when I can.