OK, a few questions if you will indulge my massive ignorance.
One, a resistor was mentioned on the line going to gate from the arduino. What kind?
Secondly,
Also, don't forget to connect the ground of the +12V supply to the ground of the Arduino.
Ok, makes sense. And by this do you mean the ground on the digital side? I see two on the board. One for each side. I just want to confirm I'm not doing this backwards.
Thirdly,
Also as drawn that diode is the wrong way round, the cathode should be to the positive side of the supply. In other words it is normally reversed biased.
Gotcha. I checked and realized that I drew it wrong. I need to follow the "valve rule," right where the cathode hooks up to the positive so that it can shut off at positive.
And yes, pin9 is set to output, but I'm not so worried about that yet. Need to get the wiring right. Then I can get the software going. 
You guys are helping IMMENSELY btw!