Einstein went after my legs once when he was about 4 months old. After that I wouldn't let him near me. Spraying water on him whenever he got close made him keep his distance. He's been good for the past 4 months. He's not exactly friendly but he is respectful of my space. He also avoids any other people who come into the yard.
I do worry about him this winter. It gets down to -25 C at night for part of the winter. I read that Polish are not cold weather birds. I got him as a free mystery chick when I ordered my flock in February. Grandson fell in love with him as only a 10 year old boy can love a skinny cockerel with blue legs and a bad hair day every day. Einstein needs to learn to cuddle with the girls when it gets cold in January.
That's good you nipped the bad behaivour in the bud. Nothing worse than an aggressive roo. If you can keep him reasonably dry he should be fine. A good coop that's draft free but well ventilated in the eves and he should be fine. We don't have temps that low here but they are remarkably good at keeping warm. Hopefully the girls will take him under a wing!!
Polish do seem to be kid magnets. My son loves them and is often found sat out with them having full blown conversations