how did the radley house acquire its reputation? do you think it was a deserved reputation?

The Radley house is the stuff of myth because it is run down and the Radley's isolate themselves from the rest of the town in it. Boo is the subject of childhood myth and fantasy for much of the novel. In Chapter 1 Scout describes Boo as a "malevolent phantom”. Apparently, according to Scout, he only comes out in the dark. He is over six feet tall and dines on squirrels and cats.

No, it doesn't deserve that reputation. The reputation is based on childish rumour and innuendo.