>Is there a gold standard for credentials?
Being NGH (National Guild of Hypnotists) Certified or attending a school like Omni Hypnosis down in Florida or one of Cal Banyan's courses is considered about as good as it gets but there are many courses available online nowadays as well - obviously if you want to be a real hypnotherapist an online course won't do, the training needs to be face to face and with real live human folk in their presence.
>What are some good "regular" places to look for info?
Hypnosis(dot)com, literally is a great starting point, so is Hypnosis(dot)org. It's not an absolute requirement to have any training in psychology or psychotherapy to be a licensed certified Hypnotherapist but choosing a professional course (like the ones already mentioned) will prove beneficial down the line.
>Any texts that are bible-like as far as you guys go?
Read everything you can get your grubby little hands on by Milton Erickson - there's a "Complete Works" PDF file that's like 1700+ pages and it has every scholarly article he ever had published while he was alive. Find books on the power of suggestion and how to properly word them (without the use of negatives in any context, etc), anything by Ormond McGill be it books or videos or whatever training materials you can track down.
As for the question about police and the use of hypnosis, while it does get some use in some law enforcement, it has long been understood that memories like most anything else can be imagined and people can lie while in a state of hypnosis just as easily as being fully conscious - there's nothing really miraculous or mystical about hypnosis once you truly understand what's going on.
Of course, to the layman or laywoman some things that are possible while in a state of hypnosis can seem to be just that, however - miraculous and mystical bordering on the impossible.