You should certainly try to run 91 or better. If you run 87 in case of emergency it wouldn’t be the end of the world as the computer would compensate for that by pulling timing. However you SHOULD RUN 91 (minimum) at all times if you can do so. Most newer cars have (2) different fuel maps and can change the timing as need be if they sense lower grade fuel. But since you have a high performance vehicle you shouldn’t use anything but premium fuel.
You could add an Octane booster of sorts to increase the octane rating. You do not have to drain the gas tank. You can also just be light on the gas pedal and burn up what you have. Again this is not a Major issue for you. Just take caution.