Power or none, the 9-inch drum brakes were adequate for the lightweight '64 Valiant in 1964 traffic. They were questionably adequate on the larger, heavier Dart, and their inadequacy grew less and less arguable as the cars got heavier and the traffic got denser. There's a variety of good options for upgrading. See this thread (login required and worthwhile).
2. Is it worth buying JEGS steel brake lines vs making your own (my thought is I don’t have to buy tools )
Yes, but you're better off getting a better-than-stock setup built by a good local exhaust shop. Good recipe is here; it works just as well (with a 2-1/4" headpipe) for an upgraded stock single exhaust.