I calculated my final grade because the prof posted our final exam mark.

I calculated 89.65.. Would that count as a 12 or an 11?

If its an 11, would emailing the prof to bump it help?

It's an 11, since 11 encompasses anything from 85.0-89.9. There's no rounding involved in that.

Some profs will automatically bump stuff like that. Some won't even if you ask them.
You can ask, but they're not in any way obligated to since you didn't actually earn the mark.
An alternative is asking to see your exam to see if there's any place you could get extra marks...you could phrase it something like "I'm really close to the next grade level and I just want to make sure everything is okay with my exam"...adding errors can happen, too.

Check the course outline to see if it states "all borderline cases will be reviewed and marks within 0.5% of the next grade point on the McMaster 12.0 scale will be rounded up to the next grade point." If it does not, most professors skim through the grades, for small classes anyways, and then determine if a particular mark should make it to the next grade point.

For example, if you have an 84.70% and ten students have marks higher than 84.80% but lower than 85.00%, then they have a higher priority of being rounded up. If you are the first on the list, meaning the closest anyone is to an A is 84.70%, then you will get rounded up. All this, if the professor chooses to. It is possible for an 84.85% to be rounded up to an A, while an 84.65% stays at an A-. Exam marks are also sometimes looked at when making such decisions. Hope that helps.

Yeah it's possible. Wait until you get your official. I've had marks posted on avenue that were on the border of the grade points and ended up being a higher grade point on the grade report.