Sounds like to me he [Kennedy] will rule against the Government. I see the words "of the state" to mean that of the government as the whole, or referred to commonly as "the state." However, there is in fact a constitutional issue with forcing individual states to adopt exchanges. If a state has created its own insurance market, it has done so specifically because it was a power not delegated to the Federal Government to implement under the Constitution, therefore it stands to reason that the government may not force a state to participate in the federal exchanges. If he rules in favor however, the insurance market will collapse. Making states implement a federal exchange will essentially send the state insurance markets into what Kennedy dubbed a "death spiral."
I'm predicting as of now a 5-4 vote overturning Obamacare. Quote me on that if you would like.