Hello,
To disable sidebar on My account page edit page and select in the page settings “Without sidebar” http://prntscr.com/btyffe
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.
Add the following code in custom CSS (Theme Options > Styling > Custom CSS)
.woocommerce-MyAccount-title { color: #FFFFFF; }
We’ll fix it in the next update.
Regards