You Canadians are lucky. We only get 91 in CA, land of the super green fruit and nut politicians who don't know that more octane in an engine built for it gets you more power and more mpg. Or that too much ethanol causes fuel line and gasket repair bills. It's ok in my self powered lawn mower, because I can't run that fast behind it anyway.
Just for giggles, I put a half tank of 100 race gas in my other high performance car yesterday. That brings the blended average to a 95 you can feel in the butt-o-meter. And that tuners can document on the dyno. They sell 100 at every race track for a reason. Granted, a Lexus is not a race car, but just use what the manual says, no less.