How can I see the actual cursor position? Usually, other editors use the status bar for this, but I can not find where is the option to enable it (even checked with the dconf editor).
Is there a plugin for this?
(I'm on ElementaryOS, Freya)
There is currently no such option or plugin. You should probably file an issue report against Scratch. See this other StackExchange post: How can I report an issue with elementary OS to the developers?