Wolves by shore, worrying beast of burden (9)
I believe the answer is:
packhorse
'beast of burden' is the definition.
(I've seen this before)
'wolves by shore worrying' is the wordplay.
'wolves' becomes 'pack' (pack of wolves).
'by' says to put letters next to each other.
'worrying' is an anagram indicator.
'shore' with letters rearranged gives 'horse'.
'pack'+'horse'='PACKHORSE'
(Other definitions for packhorse that I've seen before include "Beast of burden" , "animal" .)