Header v9 is a pre-configned header layout of context. In order to select it, just go to customize> header> header layout and select prebilt header as header v9. With all header layouts, you can select header background, text color, set the height in the customizer. Besides, The Topbar Can Be Configured Separately.
This header layout supports both the header main and header botttom sections. You can set the height and background, text color for ite sections in customize> header. The height of the site header will be the total height of header main and header botttom.