Oh, good grief.
He was just brought to trial NOW, which is why he was just sentenced NOW. The victim waited until NOW to charge the guy. Fortunately for the victim (and other possible victims), there appears to be no statute of limitations on child molestation in this state (or it is a very long time).
The sex offender registry law went into effect long after he had committed the crime. The law applies to when the perp COMMITTED the crime, not when he is CONVICTED. Megan's law was not a law when the perp committed the crime, therefore it does not apply to him.
This is an excellent demonstration of our constitutional protection against Ex Post Facto laws. I do not personally like the result, but this is exactly why it was included in the Bill of Rights; so that nobody can be punished retroactively by a law that is written AFTER the fact.