[J-Man]

Without knowing the voltage requirement of your setup, I would stick with a 9VDC power supply. A 1000mA supply should be enough but it doesn't hurt to go with more capacity, just be sure it's a REGULATED 9VDC. If the power supply is not regulated, it could output more voltage than the listed rating.

 

[J-Man]

I'm no electronics genius, and I'm sure one will correct me if I'm wrong, but batteries are DC, not AC.

Not sure of the point you're trying to make. A 9VDC power supply is just that, DC.

 

[J-Man]

Just thought, how do you know if it is a regulated or unregulated power supply?

Check the voltage using a meter with no load on the power supply. If it's regulated, the reading will be the stated voltage. If it's not regulated, the reading will be much higher than the stated voltage. As mentioned earlier, if you have been using a 9V battery, just stick with a 9VDC power supply.