> "Can I somehow put a tracking device on my young child?" is a question I've thought about for decades

Good for you and those like you, it's nice when something long-awaited finally drops. I was speaking of the people who, if prompted 20y ago, would have said "that's creepy" but are now cool to track their kids, set up cameras around their house that are controlled by 3rd parties, and be cool with a firm tracking everything they watch, etc.