How to change UIAlertController button text colour in iOS9?

I’ve run into something similar in the past and the issue seems to stem from the fact that the alert controller’s view isn’t ready to accept tintColor changes before it’s presented. Alternatively, try setting the tint color AFTER you present your alert controller:

[self presentViewController:strongController animated:YES completion:nil];
strongController.view.tintColor = [UIColor black];