I've checked the official Florida registry and got nothing. The disclaimer in the linked site says results might be out of date. In addition, as a privately maintained registry, they have no obligation to remove or maintain anything. Still, I googled the legal name and it checked out with the alias which means that at one point in time, he might have been on the registry, but as of right now, that's not the case.
I also googled the name of the private registry site and a lot of people are angry about it having out-of-date information. It also requires people to pay to get their names off, even after they're no longer legally required to be on the official registry. Some were placed on it without even committing an offense worthy of landing on the registry. Nevertheless, the site says he was charged with a violation of Florida State Code 800.04(4):
800.04 Lewd or lascivious offenses committed upon or in the presence of persons less than 16 years of age.—
(4) LEWD OR LASCIVIOUS BATTERY.—A person who:
(a) Engages in sexual activity with a person 12 years of age or older but less than 16 years of age; or (b) Encourages, forces, or entices any person less than 16 years of age to engage in sadomasochistic abuse, sexual bestiality, prostitution, or any other act involving sexual activity commits lewd or lascivious battery, a felony of the second degree, punishable as provided in s. 775.082, s. 775.083, or s. 775.084.
As for when, it doesn't say. It could be a 4a: one of those cases where he was in his youth and there was an age gap between him and the girl and the parents decided to legal up. In these cases, the men (and sometimes both minors) are labeled sex offenders even if it was consensual (remember–minors cannot give consent in the eyes of the law). I think this might have been the situation, remember, he's no longer on the Florida state registry. If it was 4b, they would not have removed him that quickly. Then again, we don't know when this happened.
If 4b is what transpired (and not a case of age differences and the law), then it's extremely sickening. Forcing yourself upon a child is never acceptable let alone attractive. It could explain why he's turned to porn, ending up on the registry is basically a life sentence. People avoid them like the plague.