If a provider was to recieve a threat from a hobbyist in another form of contact like IM, text or otherwise, is there anything the provider can do to expose him or would it just be "he said ...she said"?

Was that a threat of physical harm? He was betting that you wouldn't report it to law enforcement.

Maintain a record of the threats, time the person called, e-mails, etc. Most IM programs have a transcript feature that you can print. Get serious about turning him in reagrdless of what you think you have to lose. Nothing is more precious than life.

Remember one thing, a threat to harm today can be considered a "terroist threat" and he can end up behind bars for a long time.

What you do not have to say is what your profession is, just prove he has made threats against you and all those copies are proof.

Be sure it has his name in them, also do you have his Email or other personal information?

Crossexamination at trial:
Defendant's Atty: "And just what is your profession, miss jones?"
Your Atty: "Objection, your honor. My Client's profession, whether dog-walker, schoolteacher, or fashion model, is irrelevent.  The only legitimate question before this court is whether or not the defendant made threats. Our evidance shows he has."

Gather your evidence, and if push comes to shove, find an attorney that will defend you while prosecuting the bad guy.