Android and Ren'py don't play well together, unfortunately. Certain combinations of OS and hardware will cause Ren'py games to glitch out, freeze up or just straight crash. There's only three potential solutions I've ever seen work:
1. Free up more storage space.
2. Fully power down and restart your device
3. Ensure that your phone is completely up to date
Failing that, the only alternative is to download JoiPlay from the Play Store and run the WIN version of CK through it (although JoiPlay itself can be unstable).
Sorry I can't be more help, but this is an SDK/Device issue and I have no control over either of those :/