The reference to AutoZone, which is an American car parts retailer, suggests that this post comes from the USA. That might help us (on this UK-based website) to understand the term 'substitute teacher'. In the UK we'd probably take that to be equivalent of a supply teacher (who covers in the absence of a regular member of staff).
Supply teachers need to be fully-qualified to university degree level in the same way that other teachers are.
However I suspect that 'substitute teacher' in this post might be the equivalent of our 'teaching assistant'. (In the UK teaching assistants work alongside, rather than in place of, qualified teachers. Although they don't need to be educated to degree level, they still have to possess relevant academic qualifications).
Lots of men enjoy working alongside young children (e.g. within the Scout movement). The vast majority of them don't pose any risk to the children they work with (and, indeed, do a great deal of good), so it would be wrong to jump to any negative conclusions about someone who says that they'd like to work with children. [That's in response to the 'creep vibes' bit of your post]. However anyone who thinks that working as a teacher (or teaching assistant) is an easy job clearly doesn't understand what the job actually entails. Apart from anything else, there's a load of detailed record-keeping to be dealt with, for a start.