You could do it with three transistors and five resistors per digit;
Assuming Common Anode
Use a NPN to turn on/off your pnp connected to your Anode, and use the other NPN to ground your Cathode.
You'll need a resistor divider between your 9v supply and the base of your PNP transistor, the centre of the divider would go to the Collector or the first NPN transistor, and a resistor for the base of that NPN transistor to the micro.
For the divider the resistor connected to the 9v supply could be 10k, it's only a pullup, the resistor going to the base of the PNP would control the base current when grounded by the driving NPN.
Then a current limiting resistor for your segment and a base resistor for the NPN puling the Cathode to ground.
So, for a single seven segment display (Common Anode including dp ) would be x1 PNP, x9 NPN and 22 resistors, for each additional display you'd add x1 PNP, x2 NPN and another 3 resistors.
A lot of trannys.
Multiplexing, just connect all common segments together.
CC are much simpler, as is a single supply
Hope that makes sense