This could have been due to sellers of $10 call options hedging their positions in a very thin overnight market, or equally, one or a few players aggressively executing their orders in that illiquid situation. The timing may reflect non-US trading hours (e.g., Asian buyers) or simply a decision to trade outside of regular hours despite thinner liquidity. In such an environment, even small trades can cause sharp, temporary price spikes, as seen with the $9.70. A broader analysis can be found on Reddit.
In any case, a high of $9.29 has already been reached, meaning that psychologically crossing the nine-dollar and eight-euro marks will be easier in the future.