I can't see any mention of the feature being delayed. I'm on the iOS 26 RC, I'm on an iPhone 16 Pro with Apple Intelligence, and my AirPods Pro 2 are on the latest beta firmware 8A343a. So, I believe it should work. (As per Apple's availability overview.) Yet I don't see any option to enable it in Settings or in the iOS Translation app.

Has anyone figured it out yet?