I'm not sure what the law is for sex offenders in your state..esp with it being juvenile. You may want to look into getting it expunged b/c you will have to get a background check when you get your license to practice.
Private security laws are regulated by the state, so the laws may vary where you are at. Generally though, laws regarding security vehicles are minimum because they are not emergency service vehicles so they must obey all regular traffis laws (though I have seen a security vehicle run a red light with flashing amber lights but this was illegal). They are granted no special traffic privaliges unless specifically granted by the local police. (usually these are security companies that are contracted by the government to patrol certain areas). In regards to light bars, they are also losely regulated. Blue lights signify law enforcement, red lights are for extremely hazardous conditions, and amber lights are for unusual traffic hazards. For the most part, only blue light may be prohibited by law and amber lights can be used by anyone such as construction crews to tow trucks. Red light laws vary place to place. As a security vehicle, amber light are totally acceptable because they create visibility and crime deterence bu talso could mean that your vehicle is subject to frequent stopes which pose a traffic hazard. The decals you will have on your vehicle will let everyone know you are security and not trying to imposter any public safety agency. So as long as you don't run red lights and driver faster then usual with lights on trying to act like a emergency service, then you will be fine.
As for a police scanner, public safety frequencies are public frequencies where everyone can listen to them. So having one in your vehicle in plain site and turned on is absolutely legal as long as your aren't using it for criminal purposes.