Hello,
You may disable header search in Theme Options > General > Header Settings.
Search is default content of the main sidebar. If you want to make this sidebar empty just add the empty text widget into the main sidebar, or you may select Sidebar Position > Without in [8theme] Layout options for the page.
Also, try to add this code in Theme Options > Styling > Custom css:
.home .content-page {
margin-top: 2vw;
}
Regards