I can't speak to what tutoring agencies in Calgary would be good, as I don't live there.
However, I tutored a ton of math/science in university. I did it privately, at tutoring agencies, etc. There's no real way to know who will help your child the best unfortunately without trying.
The school she's attending may have a program (schools in my hometown did) where tutors come in and help students. You can try calling the local university and see if they recommend any students to help your child. Or you can put an ad out in the paper or online and see what comes from that. Like a classroom teacher, it is ideal to get someone who connects with your child. And by that, I mean that the way they explain things "makes things make sense".
It may be beneficial to have one tutor or it may work better to have a chemistry one and a physics one.
Good luck in your search
