I believe the judge's declaration of unconstitutionality comes from his dismissal of the crowns request for a 150 year ineligibility for parole. Essentially saying that removing his hope of ever being able to leave prison would constitute cruel and unusual punishment.
I believe a Superior Court Judge can deem a law unconstitutional, though when it happens these are generally appealed allowing higher courts to make the final determination. I think this is only coming up 6 years later because its not too common in Canada for situations to arise where the implementing of such penalties is required. If there's no case at bar, there's no reason for the constitutionality to be explored unless the question is referred to the courts by government.
Should state that i'm not a criminal lawyer, so some of my statements could be incorrect