Finally finished after taking a break and coming back to it with fresh eyes.
As others have said, the cold solving is rather daunting at first but, once you manage to place a couple of the 9's, everything falls nicely into place.
I knew the song from a recent TV programme where a guy sings it while merrily working away.
I particularly liked the endgame and how the "late arrival" married up with the relevant name.
Thanks to Aragon for a thoroughly enjoyable puzzle from start to finish:-)