is it possible to create evil genius children

It depends on your definition of evil. If you adopt values you regard as evil when the child is young and always present them as perfectly normal, the child would be socialised with an "evil" morality just the way we normally socialise them with the values we unthinkingly hold. In order to prevent the child from rebelling against the values you instil when it gets older you would probably have to find a way to discourage critical thinking - but if you stunt its mind in this way you might affect its propensity for genius. Difficult one. will try it in practice and let you know.