The US might extradite you if Australia could make that case. Especially if it could be proven that you would receive a fair trial and no cruel or unusual punishment. That's what's happening here. The UK can still refuse to give him up if they don't make a good enough case.

For context on the issue of "fair trial": look at cases of worse charges than conspiracy to hack, like Maria Butina, for instance. She still received a proper trial and chance to defend herself against the evidence. Our legal system is broken in many ways, but mostly when it comes to racial or income inequality and local law enforcement. On the larger stage the rules for these things are pretty clear.

If you want to see some contrast take a look around at other large nation's justice system.