Turn 9V device off using 3.3V logic level signal
Change your load-driving PNP for a P-channel MOSFET.  Also, you want a pull-up resistor on the gate of that MOSFET to ensure it switches itself off when the NPN switches off.

The NPN should also really have a pull-down on its base to keep it off when its input is HiZ or disconnected.

This is a circuit I use all over the place: