How does one go about getting the opportunity to become 12B K9 handler?

Yeah, that's what I assumed

So it is no longer an added identifier to your mos? It's own mos. That have helped me when I was in. Went to a unit and was told they were not going to put me in the kennels, they wanted me to work the road. It wasn't like they were short, roughly 130 MPs in the company between 2 platoons plus the HQ platoon (not counting the kenels). Less than 10 E3 and below, eveyone else on the road was E4-6. Shift consisted of 12 folks max. So it isn't like they were hurting on manpower, just Top wasn't going to put me in the kennels. If it hand been an MOS he would have had to put me there to fulfill the slots. Oh, and they were hurting for manpower in the kennels, a few guys were having to work 2 dogs because they were short. Once I got over there about 8 months later I was working to dog's. And no, I did not have any disciplinary actions that would have kept form doing it, although I did get disgruntled because the DA had sent me there because they were short and needing handlers. Yeah I'm old 95B10-A9.