Class 9 student, need some advice

Hey everyone, I'm a class 9 icse student aspiring to become an IITian. I consider myself to be above average and my aim is <1000 AIR in Advanced (is it too unrealistic?). I had some doubts about how to study. 1, is it necessary to start studying class 11 concepts from now, like some of my peers do? It really makes me feel like I'm wasting valuable time. 2, will coaching material be enough for such a tough exam or will I require reference books too. If I will, could you list the best books you've solved for each subject, I've seen people recommending many books at once but idk if I'll be able to finish them all in 2 yrs. Lastly, could you please give me some tips on how to study smartly and reduce mistakes, I make silly mistakes a lot under time pressure. Thanks for your help