`mw-cite-backlink` is styled with `user-select: none;` in `ext.cite.css`. When using IE9, the backlinks` ^ab` do not display due to this property.
This property is not supposed to be supported by IE9 but, apparently it causes the content to not display. IE8 and below do not support this property at all; IE10 and above support it properly.
This can be fixed in user CSS with:
But obviously does not help anon readers.