hey!
the essay writing when i did it was just 15 minutes for one, but i think (correct me if i am wrong) it has changed to 30 minutes and only one essay. if you wanted to get a headstart on preparing it might be a good idea to practise writing an essay a few times a week, and getting someone to give you feedback, just to get into the habit of writing under time pressure.
look through the year 9 maths textbook, and familiarise yourself with the content.
i would also suggest doing maybe one hendersons mock exam, which i found was very helpful in consolidating weaknesses and strengths, although if you opt for this do it closer to the actual exam next year.
i would say more than just studying, immerse yourself in many extracurriculars and leadership opportunities, as selective schools often looks for well rounded students if it comes to the interview process.
good luck! it's great that you have started prep so early, but keep in mind that the selective schools are just that, schools. at the end of the day they have their own pros and cons and it really really is not a gateway to a perfect atar of your dreams. regardless of what school you go to, anything you want to achieve is possible.
feel free to ask any more questions!
