After installing an Enterprise app build to your iOS9 device you may be presented with a dialogue box upon first open saying:
This is nothing to worry about. It is just a safety precaution put in place by Apple. What you will need to do is navigate to Settings > General > Profiles
Select "Mogeneration Pty Ltd" and then tap the blue "Trust Mogeneration Pty Ltd". This will then allow you to open the Enterprise application you installed.