Guessing by eye, you could cut to between 11.5 and 10.5, and get rid of the damaged section.

That's an unusually large amount of damage for a squib with a pistol caliber round, though - the others I've seen in 9mm (Uzi barrel and a glock barrel) have resulted only in a bulge and a dark mark in the rifling, not long, ragged, multiple cracks like those appear to be, with rifling completely missing at the bulged section.

Definitely get it tested if/before you decide to cut it down and re-use. Seeing that much damage, I'd personally just trash it and get a new barrel to start from, rather than take a risk.