The 87 octane is NOT the cause of the lack of power. These scooters run fine on 87 so put that out of your mind.
It sounds to me like a CVT issue. You should pull off the left side cover and inspect the belt, pulleys and weights for wear. The weights can get flat spots on them and that can cause them to hang up. Also the belt wears and that rubber dust is not a good lubricant so it needs to be cleaned out periodically. I use an old long bristle paint brush. You don't have to get every spec. Just get most of it out of there. You'll need to get an impact if you don't have one. Harbor Freight has them as well as Ebay. Search for "12 Volt Emergency Impact Wrench"
This video will show you the procedure for removing the CVT components.
http://www.youtube.com/watch?v=hyb9NyR-SjsThe impact is like this:
http://www.harborfreight.com/12-volt-1-2-half-inch-emergency-impact-wrench-92349.html Also, if there is a clear tube coming off the air filter box full of oil then pull the plug and drain that tube. That's the oil catch for the crankcase vent line that comes off the valve cover. If its gets full of oil it can suck oil into the carburetor. Not good.
This pic shows one version of the crankcase oil catch:

Lastly, a valve adjustment could solve the issue. It's extremely important the valves are gapped correctly. Here's a guide for that:
http://www.scooterforumonline.com/index.php/topic,1720.0.htmlGood luck and keep us posted. Inquiring minds want to know what happens.