Learning to ride out in formation (9)
I believe the answer is:
erudition
'learning' is the definition.
('erudition' can be a synonym of 'learning')
'ride out in formation' is the wordplay.
'formation' is an anagram indicator.
'ride'+'out'+'in'='rideoutin'
'rideoutin' with letters rearranged gives 'ERUDITION'.
'to' is the link.
(Other definitions for erudition that I've seen before include "Learnedness, scholarship" , "Great knowledge" , "Learning, scholarship" , "being widely read" , "Great learning" .)