There is no EyeX Engine API functionality to turn on or off the eye tracker. Since it is a client/server system, we don’t want to allow clients to disable server functions so other clients do not get any data. You can manually enable or disable the eye tracker by right-clicking the EyeX icon in the Windows notification area and toggle “Disable Eye Tracker”.
As a workaround (hack), you can try to use regular windows commands to kill the EyeX Engine process and the Tobii service. I would not recommend that though.
Reliability/confidence values are not implemented in this generation of eye tracker, but might be a future addition. What do you want to use the reliability value for?