C9 works great in Opera 9.5. But I noticed some quirks. When I want to write a post, the Add and Cancel buttons are visible, but I can't click them, because they hide behind some transparent panel. When I click the HTML-tab, the layout of the editor changes and the buttons are moved and become accessible. The editor itself also acts quirky sometimes (like when you select text and press Delete, the editor will delete the selection, and the first character after the selection), but at least I now have a proper rich editor that can be used in Opera.