Are you watching children at an elementary school? I assume no....so that's not what is going on. But as long as you're maintaining yourself and not acting in any inappropriate manner, why would it be creepy? I ignore messages that aren't directly related to my content or the conversation to avoid that area. Just be to the point, and if you ever feel like it's too much that one is messaging you, then you can block them or ask them to stop and explain they shouldn't be talking that much to you anyway. It doesn't have to be creepy, the only one that can make it creepy is you. because the kid isn't talking to you to be creepy.... It IS possible believe it or not to be a positive role model for kids and not be a weirdo.
Also Unc is short for Uncle , yes. But it's a compliment in modern slang words. They look up to you. Be a role model. And you won't be looked at like a creep.