Moving, a line by English Poet Laureate (9)
I believe the answer is:
emotional
'moving' is the definition.
(moving can mean very emotional)
'a line by english poet laureate' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'by' says to put letters next to each other.
'english' becomes 'e' (abbreviation).
'poet laureate' becomes 'Motion' (Sir Andrew Motion, UK Poet Laureate 1999 to 2009).
'a'+'l'='al'
'e'+'motion'='emotion'
'al' put after 'emotion' is 'EMOTIONAL'.
(Other definitions for emotional that I've seen before include "Worked up, upset" , "Thrilling" , "Arousing strong feeling" , "Heart-warming" , "expressing feelings" .)