You are living in Texas? Yes? No? I taught there for years with an old DUI on my record, but I had an advocate within the district and prior successful teaching experience. I was questioned pretty heavily about the incident though. Interestingly, when I moved to my current state I got a job with no questions asked. I mean, I was required to disclose it in the application process, but no one was concerned or asked questions.
Overall, living in a more "liberal" state has its advantages in that there's not so much fear about teachers' having flaws and vices. You might consider moving. There are many things I miss about teaching in Texas but it is a puritan culture, at least in the suburbs and rural areas.
Also: research the meaning of "moral turpitude" in Texas (it varies by state). I remember that my DUI did not constitute a moral turpitude and that's why it was not a hindrance to my hiring. Doesn't mean you might be overlooked because of a past record, but unless the crime falls into a specific category of crimes that constitute a moral turpitude, there is no legal hindrance to being hired.
Is it hard to get a band teacher job with a record? What about lesser crimes and misdemeanors? What if it was years in the past? And you have a outstanding resume.