Has a Copa America game ever ended 9-0?
Yes. Copa America has seen a final score of 9-0 4 times. It first happened on November 6, 1927, when Uruguay beat Bolivia, and most recently on March 24, 1957, when Brazil beat Colombia.
That makes 9-0 the 23rd most common final score out of 36 that have ever occurred in Copa America. One point away, 10-0 has happened never and 9-1 has happened 4 times. At one point the score disappeared for 30 years, between 1927 and 1957.