Our installers are signed so you shouldn't be seeing that message. We'll have to check if the certificate we're using to sign pre-Yosemite builds expired.
In any case you just need to adjust your security settings to run the installer. Click on the Apple icon in the upper left hand corner of your screen and open System Preferences. Go into "Security & Privacy" and change your settings to allow apps to be installed that are downloaded from Anywhere. If you want you can change that back to what it was after installing H9 Control.