I figured out why Walt left the nine million to Walt Jr and not Skylar. It just wasn't to support the family. He wanted his son to never miss breakfast again. When Walt called him at school he wasn't mad at him for what he did to Hank, he was mad that his dad never invited him to breakfast. He didn't visit Walt Jr before he died because he knew that he would be mad that his dad didn't invite him to Denny's to celebrate his 52nd birthday. He gave him nine million so that way he would have enough money to have breakfast whenever he wanted.