That cable would work as long as the voltage from the battery is reduced to 5 volts before it goes to the JB3.
However you would not be able to use a mostly drained 9 volt battery to power the JB3 without the power going through a regulator. 9 volts will fry the JB3.
Using a ToddR* "juice box" I have powered both a UA5 (with phantom on) and a JB3 for over 4 hours with a WallyWorld DVD batt.
To use a UA5 and a JB3, you will either need two batteries, a 9volt and a 5 volt; or one 9volt battery and a voltage regulator box with both a "pass through" output and a 5 volt output.
One last time, you can not run a JB3 on 9 volts.
* ToddR and leegeddy both made voltage regulator boxes. Other TSers did as well but I've only used VR boxes from those two.