MAX7219 questions

Hi,

I'm rather new to electronics, but I'm planning to make a physical model of a street scene, with street lightning I can individually control.

The MAX7219 seems to be a good way to implement this, but I still have some questions.

1) On the hardware scheme, I'm unsure where the "Vcc(+5V)" wire must be going to? Is this the 5V pin on the Arduino? Schematic see next post!

2) I want it to be mobile and already have a 9V battery connected to a barrel jack right into the Arduino, so I want to use this for simplicity of the circuit. Will this be ok? My Arduino will be controlled by Processing, so an USB connection might also be powering it at the same time. Or doesn't it? LEDs are white super bright, so will this be enough? They won't be all lighted at the same time, however, so might be more forgiving...

3) What's an efficient way to make the matrix of LEDs? Schematic see next post! I could make it just with wires, LEDs and soldering, but I can imagine it would become rather messy. Any other options, like prototype boards or something like that.

Your help is very welcome :)

Thanks in advance!

Additional info for my previous post:

MAX 7219 hardware scheme http://www.arduino.cc/playground/uploads/Main/MAX72XX_SPI.jpg

LED matrix wiring http://www.arduino.cc/playground/uploads/Main/LedMatrix.jpg

Is this the 5V pin on the Arduino?

Yes.

I want it to be mobile and already have a 9V battery connected to a barrel jack right into the Arduino, so I want to use this for simplicity of the circuit. Will this be ok? My Arduino will be controlled by Processing, so an USB connection might also be powering it at the same time.

These appear to be contradictory statements. Either the Arduino is connected to the PC, using the USB cable, so that Processing can talk to it, or it isn't and it is mobile.

Battery and USB at the same time is not a problem, but, if it is connected to the PC, the battery is unnecessary.

3) What's an efficient way to make the matrix of LEDs?

Buy one.