Kids climbing over A-road? Might be right (9)
I believe the answer is:
starboard
'right' is the definition.
(right side of a ship)
'kids climbing over a-road? might be' is the wordplay.
'kids' becomes 'brats' (brat is a kind of kid).
'climbing' shows that the letters should be reversed in order (in a down clue, letters climb up).
'over' is a charade indicator (letters next to each other).
'might be' is an anagram indicator.
'brats' back-to-front is 'starb'.
'road' is an anagram of 'oard'.
'starb'+'oard'='STARBOARD'
(Other definitions for starboard that I've seen before include "Ship's right side" , "Right-hand side of ship while facing forward" , "Right side at sea" , "Opposite of port" , "Sailor's right" .)