To elaborate, higher octane fuel exists solely to prevent self-detonation in higher compression engines by slowing the fuel's burn rate.

I suspect that when operation in compression-detonation mode, it will inject the fuel late enough into the compression stroke that the difference between 87 and 97 octane fuel won't be that big of a deal.

If it does make a difference then I would expect they would design for the higher octane rating gas to prevent user-error.

I anticipate the engine's control computer will be able to adapt in any case. It's like the Mercedes driver who puts in 87... it'll work, and the gas is cheaper, but the tradeoff is the engine runs in "poor fuel" mode and is less efficient, eliminating any savings.