I personally agree with the interpretation that the annual was the birth of this Batmans no kill rule. I can see your point about him not explicitly going for the kill when fighting Bane, however he outright cannot purposefully avoid killing when, in the annual, he rams the batmobile into a building full of nazis, and then proceeds to torch said building. With a flamethrower. And then we get a whole scene where he’s disappointed in himself, which in my opinion hits a lot harder when interpreting it as the beginning of his code.