I want to do a simple thing - I want to be able to turn the power from a 9v battery on and off via wifi. The device I want to control is a smoke detector based door hold open. I want to be able to cut the power from the 9v cell, which will cause the device to release the door, and the door to close under its own self closer.

The device, and whatever powers it has to fit in the small compartment where the 9v battery fits, a space about as wide as a 9v cell, and about as thick. If there is room I can fit an additional power cell for the device, but I am concerned how long it will run on wifi. It may be possible to make the device power up wifi and check status only once every 15mins.

So will a TinyCircuits device fit?
I know there are Wifi boards, but how about boards that could switch the 9v power.
Is there a web based control panel that would communicate with the device, and I could use to cut the power, set a schedule to cut it at a preset time every day?

I realize this is an old post and you have probably solved your problem already but the DUAL MOTOR TINYSHIELD (ASD2302-R) says it supports up to 11 volts.