Corrosion and acids do the damage. Acid will kill the bearings and
corrosion will kill the crank journals.
So you drained 9 liters of water from the
oil sump, or was that 9 liters total,
oil and water? How did it get in there, through the breather? Which would mean I guess, the engine was under water? I suppose 2 bad seals in the
raw water pump could do that after a while or maybe a really bad rear main seal. 9 liters of water with 6 quarts of oil on top is probably right up to the crank. 9 total would be below the crank, me thinks. If it were 9 liters + 6 quarts of oil, you are probably right, the crank at least, is toast without a re-grind. All the other important stuff might be OK, or perhaps repairable.
Where in
Panama are you? If you are in one of the popular areas like Colon or Panama City, you have more choices. Panama might be 3rd world but you can get your engine fixed down there.
That said I would have reservations about
buying a already"rebuilt" engine from just anybody up here or down there. If you were in control of the operation you might have better luck.
Perkins still sells gaskets, bearings, cylinders etc. etc. but yeah, no support other than parts.