In my area, 90-91 ethanol free is available at almost any gas station. I run that in everything I own from chainsaws, to boats, to wheelers, everything. Only exception is my wife's 2018 truck. I would run that if it's readily available in your area.
As far as running 100+ octane in an engine that can safely run 87, you will actually lose a little bit of performance running race fuel. High octane race fuels are meant to run in high compression engines without detonation. It wont hurt your engine at all to run higher octane than is necessary, you'll just lose a little bit of power, might not even be that noticeable in the seat of the pants. If those types of fuels are all that's readily available to you for ethanol free, I would run it just to avoid the headaches of ethanol, especially in premix running two-strokes.