Although adTempus offers a few ways to "kill" an application, these all rely on a method that can cause problems such as unsaved files and corrupted data.
If you're looking for a way to close a program cleanly at a certain time, and the program doesn't offer any built-in way to do this, the best approach is to send the program whatever keystrokes will cause it to close.
To do this you can create a Script Execution task or Script Action that sends the keystrokes.
Note, however, that if the program is running under a different account than the job you're using to close it, you might not be able to send keystrokes to it.