Titbit is gobbled up by a page boy (9)
I believe the answer is:
appetiser
'titbit' is the definition.
(a titbit is an appetiser or sample)
'is gobbled up by a page boy' is the wordplay.
'gobbled up by' indicates putting letters inside.
'page' becomes 'p'.
'boy' becomes 'peter' ().
'a'+'p'+'peter'='appeter'
'is' put into 'appeter' is 'APPETISER'.
(Other definitions for appetiser that I've seen before include "Small starter dish" , "Relish" , "bonne bouche?" , "stimulating food!" , "dim sum?" .)