It almost certainly won't be at launch, as the kbin API is not ready yet. Artemis, another upcoming kbin/Lemmy double-act app, is currently relying on a web scraper and self-hosted shim API to access kbin content, with the goal being to switch to the real API once it's available.
Basically, it's a lot of extra work to support kbin right now, but in the future it should be about as easy as Lemmy. I'll be interested to see if any other Lemmy apps pick up kbin support as a result, but even just a couple is more than I expected so soon.