I know almost 0 about voltages, electronics, anything like that, but I don't think that the ability can be fed 9v directly. I think it's rated for 9v at most but please do not trust this comment and don't try anything above 5v until you know for certain. the answers are on the forum here somewhere.
also use the 3 holes for the barrel jack that comes with the axoloti. make sure you do not reverse the polarity. good luck.
http://www.axoloti.com/product/axoloti-core/
The specs linked here say 7-14V DC, center positive.
http://www.axoloti.com/wp-content/uploads/2018/04/axoloti-core-sch-v12.pdf
The schematic shows that the X2 points are connected to the barrel connector. X2-1for ground, X2-2 and X2-3 for +.
Sorry to necro this thread, but can I ask, what is the consumption when used as a Eurorack device? Am I right to assume that it will be around 150mA? It is important to know the consumption in that scenario.
The USB will be plugged, but the controller is self powered so I don't expect it to pull off any power.