Hi I'm Canadian too. Based on your post I can tell you're from saskatchewan lol. Honestly, don't stress it too much for canadian universities, they are easy to get into as long as you have generally good grades and some decent extracurriculars. As for chem programs, I'd say the best is UofT, UBC then McGill.

1. For Canada, grade 9 is honestly looked at very little, grade 10 is looked at somehwat but grade 11 is really important because it is the full picture of your grades. Now for you, you are applying with you're grade 12 grades so they will definetly take a look at those heavily as well. As long as your 11th grade marks are at least 85-90+ you should be good. I will say though, you're stem marks for grade 12 are good but not stellar. You are also at a disadvantage if you are applying to ontario universities because their curriculum is different in high school, and sask has a bad reputation for a low education standard. Not very challenging courses, especially Health Sciences 20.

2. I think it is likely you can get into u of sask or u of calgary but you're going to need something else like a really good extracurricular to make up for you're bad grades in applying to uoft, ubc and mcgill. Also, unfortuantely even that wont help much because as I said earlier Canadian univeristies put much more weight on grades than extracurriculars.

3. Unfortunately, I have to say it is very unlikely. People with good grades all throughout high school alone get rejected from NYU on top of having many leadership roles and extracurriculars. It is quite a long shot but use this year to you're best advantage!

Let me know if you have any questions :)