Yes, underlining names of novels is a common practice. As for exceptions, some might argue that in extremely minimalist or avant - garde writing styles where traditional grammar and formatting rules are deliberately broken, the underlining of novel names might not occur. But in mainstream writing, especially when dealing with literature in an academic, professional, or even semi - formal context, underlining (or its modern equivalent, italicizing) is expected. This is to give proper respect to the work and to make it easily identifiable for the reader. So, in general, there are very few valid exceptions to this rule.
Typically, yes, names of novels are underlined. There aren't many exceptions. Sometimes in very informal writing like a quick note to a friend about a novel, you might not strictly follow the underlining or italicizing rule. But in formal writing, be it in an academic paper, a book review, or a literary analysis, the title of the novel should be distinguished, either by underlining or italicizing. It's a standard convention in the world of writing about literature.