I tried the new keyboard in iOS 9. I thought I would like the key labels changing case based on the state of the shift key. But, it is incredibly distracting and drives me crazy.The shift key in iOS is now styled such that it is very clear when it is enabled. So, there is no reason for the key labels to change case dynamically.
Fortunately, you can turn this new behavior off!
Go to Settings > General > Accessibility > Keyboard.
Via Daring Fireball