Orders yet to be transported by vessel (9)
I believe the answer is:
destroyer
'vessel' is the definition.
(destroyer is a kind of vessel)
'orders yet to be transported' is the wordplay.
'to be transported' is an anagram indicator.
'orders'+'yet'='ordersyet'
'ordersyet' is an anagram of 'DESTROYER'.
'by' is the link.
(Other definitions for destroyer that I've seen before include "Apollyon's" , "Type of warship" , "killer" , "heavily armed warship" , "Vandal" .)