Fan-less PC - Proxy Server + Fibre NBN | identify hosts on wireless

Hi there, I'm looking for a fan-less box to put into my home manage kids' access to the internet. (Internet) --- NBN RJ45 --- [This Box] --- Wireless access point ---- ***clients*** Q1: Any ideas of a good, affordable system Q2: Can I bridge the wireless so I can trace / manage MAC addresses (Or some other solution) Thanks P For the avoidance of doubt - I'm asking technical questions and not ones about kids on the internet.