What does everyone reckon their grades will be?Watch
Do they know what happened in that exam, your school I mean? They should count it as an anomaly because otherwise you are a grade 9 student, and use other evidence that shows it to put forward for your grade. Exactly the same happened in my geography mock, funnily enough. I was always getting grade 8s or 9s but in my case my teacher always put my grade as a 6, due to my result on my SATs test 5 YEARS AGO.
I panicked in my exam and read the 12 mark question wrong, and completely stuffed up my grade. Now I have got one grade as a 6, the other on the second paper as a 9.
School should understand your situation and put you as a 9, I'm pretty sure. And if not, resit the exam in autumn, you definitely seem capable to smash it out of the ball park, and you shouldn't settle for the lower grade when it most certainly doesn't represent where you are! I'm definitely doing this for geography, but of course it's 100% up to you