Q: Messaging shows blank screen after upgrading to ios 9

Hello there, aiken_m.

It sounds like you're having an issue, after you updated to the latest version of iOS 9, where part of the screen is blank. Although the following Knowledge Base article was written for apps you installed manually, it provides some great, initial steps for troubleshooting:

If an app you installed unexpectedly quits, stops responding, or won’t open - Apple Support

Restart the app

Close the app and open it again.

Restart your device

Turn your device off and back on.

Check for iOS and app updates

1. Make sure that you're using latest version of iOS.
2. Open the App Store and tap Updates.
3. If updates are available, tap Update All.
4. If asked, enter your Apple ID password. 

This article offers some additional steps as well:

Get help with the screen on your iPhone, iPad, or iPod touch - Apple Support

If you see lines, missing sections, discoloration, or poor image quality

1. Try to restart your device. If you can't restart, force restart your device.
2. If this doesn't work, restore your device.
3. If you still see the issue after you restore, contact Apple Support.

Thanks for reaching out to Apple Support Communities.

Cheers.