Child Care Provider Clearance

I live in Pa. My brother and his wife are in the adoption process. I will be taking care of the baby until my sister in law returns to work weeks after the baby arrives. (Probably 6 weeks or so) This may sound like a stupid concern... 8 years ago (when I was 18) I was arrested for stealing (goods, not money). It wasn't a felony or anything THAT serious...but I'm extremely embarassed of it as we were raised in a family that just "didn't do that sort of thing". SO, my family does NOT know. I have NO other criminal history. Not even little run-ins with the police. Since the incident, I met a great man, got married and now we have a child of our own. My concern is that I was told that I may need clearances to be the child care provider! They did say that it will probably depend on the agency. I am sort of freaking out...because I never thought this would be how they would find this out! Not that I'm living a lie...it's just something they do not need to know. Does anyone know if I would just need a child abuse clearance? Or if my brother and his wife would find out about the stupid misdemeanor on my record from 8 years ago?? It seems weird that they would check anything more than a child abuse clearance on me.... Any input is appreciated...thank you!