That’s a nice transformer, but there's a lot of overthinking going on here. You really could just use whatever 9-10V 850ma-1.2amp class 2 AC or DC linear transformer you can find. The NES like most consoles that originally came equipped with a AC transformer has a built in internal bridge rectifier. A bridge rectifier is a just four diodes that convert AC to DC. So since it has one it doesn’t rely on the power supply to already be rectified to DC. The only difference between a AC and DC linear Class 2 wall wart type transformer power supply is if it has a bridge rectifier included within it. So not only does the supply not have to be AC the polarity doesn’t matter either. Just never use a AC adapter on a console that expects DC then you're going to have a bad time.