Robert Louis, Scottish writer (9)
I believe the answer is:
stevenson
This clue is a double definition.
'robert louis' is the first definition.
(author Robert Louis Stevenson)
'scottish writer' is the second definition.
(Robert Louis Stevenson)
(Other definitions for stevenson that I've seen before include "Robert Louis --, Scottish novelist" , "Scottish writer" , "Author of 12 2" , "R L -, Kidnapped author" , "Writer of Treasure Island, d. 1894" .)