I have 2 pups at 9 weeks old brother n sister, with a domination problem.?

The male was the runt of the litter and is very small compared to his sister. She is very dominant over him. He follows her everywhere and she seems to be the pack leader of them both. Because he eats slower than her she will finnish her treat and then still his, or every toy he picks up she will take from him. She will eat all her dinner then go to his and push him away and eat his as well even if it makes her sick. She barks at him all the time and when playing together she always hurts him. When i play with them both she needs to be the centre of attention and he just sits and watches because she pushes him out the way if he tries to play. Is this behaviour ok as they are both only babies still, or should i be doing something about it. If so, What? Thanks