You can hide the bookmarks and feeds widgets from your students, but still use them yourself. Hiding those widgets from your students will free up space in the right column of their section home.
To hide the bookmark or feeds widget from students, click the visible (eye) icon. The icon changes to the invisible (eye with a slash through it) icon, indicating this widget is not visible to students in this section. Click the invisible icon again to make this widget visible.
You'll see the visible icon only after you've added some feeds or bookmarks.