Lagging iMessage banner on iOS 9

Hi everyone!
I own an iPhone 5s with iOS 9.1. Whenever I receive a message banner from iMessage and i try to quick answer pulling it down, the phone becames much "laggy", showing me the keyboard only after 5-6 seconds: this function is really unusable.

Has anyone got the same problem / a solution for this issue? Thank You!! 🙂