Older relative before day devised most of route for educational trip (5,4)
I believe the answer is:
grand tour
'educational trip' is the definition.
(I've seen this before)
'older relative before day devised most of route' is the wordplay.
'older relative' becomes 'gran' (I've seen this before).
'before' is a charade indicator (letters next to each other).
'day' becomes 'd' (abbreviation for day).
'devised' indicates an anagram.
'most of' means to remove the last letter.
'route' with its final letter taken off is 'rout'.
'rout' anagrammed gives 'tour'.
'gran'+'d'+'tour'='GRAND TOUR'
'for' is the link.
(Other definitions for grand tour that I've seen before include "educational trip" , "noble attempt at cultural improvement" , "big journey" , "long trip" .)