The most common and most likely answer to this crossword clue is the 9 letter word RETURNING
I've seen this crossword clue in The Sunday Telegraph
R
E
T
U
R
N
I
N
G
Buddy explains!
The straight part
We know that "on the way back" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case on the way back = returning.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RETURNING mean?
RETURNING verb- To come or go back (to a place or person).
- To go back in thought, narration, or argument.
- To turn back, retreat.
- To turn (something) round.
- To place or put back something where it had been.
- To give something back to its original holder or owner.
- To take back something to a vendor for a refund.
- To give in requital or recompense; to requite.
- To bat the ball back over the net in response to a serve.
- To play a card as a result of another player's lead.
- To throw a ball back to the wicket-keeper (or a fielder at that position) from somewhere in the field.
- To say in reply; to respond.
- To relinquish control to the calling procedure.
- To pass (data) back to the calling procedure.
- To retort; to throw back.
- To report, or bring back and make known.
- (by extension) To elect according to the official report of the election officers.
- The act of one who returns; a coming back.