iOS9 Untrusted Enterprise Developer with no option to trust

Take pokemon GO hacked version as an example:

In iOS 9.1 and lower, go to Settings - General - Profiles - Your app source/Carey London Limited - tap on Trust button.

In iOS 9.2+, go to Settings - General - Device Management - Your app source/Carey London Limited - tap on Trust button.

reference: http://stackoverflow.com/questions/30722883/ios9-untrusted-enterprise-developer-with-no-option-to-trust