I doubt it would work, as it requires the consent of the deity (or avatar)…as do most of the more powerful clerical rituals.
And the person has to be dead and not have a body, demons have bodies (sort of)
I suppose it could be possible for an evil deity to want to get demon avatars…but I’m not sure that they’d need to do canonization, they could presumably do something else to link them up to the GP and the “system” since Demons and Angels are very similar constructs.
In fact, in many pantheons, demons are just rogue angels that have broken away from the deity….
So, not being a priest, and having never been attached to a deity, I can’t say, but presumably some of the canonization spells involve forming the link to the godpool and the deity network. You’d do those rituals, but wouldn’t do the incarnation rituals that create the “body” as the “body” already exists.