Remember that Grade 9 is given out based on percentage boundaries for EVERYONE in the country, not how many marks you get, and any grade 9 given to you by your school for internal exams isn’t, in theory, real.
The only thing you can do is try your best. Your answer might get a 9 one year but the next year there might be an extra large number of Einstein kids and you won’t get the 9.
Seriously 9s aren’t the be all and end all. You’re doing absolutely fine by the sounds of it. Just try your best thats all you can do