On several of his 'hunts' he encountered Jedi in which he developed respect for them. After this Bane built his own equipment, would only work for the highest bidder, and had no regard to killing or abandoning a client if another offered a higher amount. In exchange the impostor taught him how to build his equipment. In short he did not kill the Jedi who was actually an impostor enemy agent.
After leaving his home, he went to Coruscant where he took a job from a criminal lord to kill a Jedi who was threatening his operations.
Cad Bane grew up in the slums of the space station New Tanya during the last part of the Galactic Republic where he started his bounty hunting career, and recognize later that many things go hand in hand with bounty hunting, in particular reputation.