RE: 8V circuit with 9V battery ?
While I don't know anyting about your camera and it's ability to cope with over-voltage a very simple way of reducing the voltage is to put one or two silicon diodes in series with the battery. You should be able to get them at any repair facility for home elctronics for acouple of cents. Each diode causes a voltage drop of approx. 0.6 V.
/Red B.