A's and B's are good. If he can cope with taking 9 subjects, then by all means do so. If he isn't interested in taking 9 subjects then 8 will suffice. As far as his vacations are concerned, tell him to focus on learning something productive: be it photography, painting, calligraphy, programming or whatsoever. These are important things that he should pick up. It will help him not only in his academic career but also in the real world. I would propose learning a language if he's into languages. Learning a language like French would help him greatly if he wishes to apply to Canada for university. Spanish/Mandarin would boost his prospects in the US. Things like these will not only allow him to be multilingual but also establish him as a strong candidate in his applications.Thanks for the information! My brother's the first in the family that's going the O/A-levels route, and I don't really know much about them either. This is a good starting point. Going to tell him to try to put some extra effort into extracurriculars as well. He's currently on vacation and I'm telling him to do his subjects that he's going to be appearing for in May 2017. Don't really know what else to do to give him an edge.
Also, if say he opts for a total of 9 subjects, if he gets a B in one, and A's in the rest, is that better or worse than opting for only 8 subjects and getting A's in all of them?