Has an Euros game ever ended 9-1?
Exactly once. On November 18, 2019, Italy beat Armenia 9-1, and no Euros game before or since has ended that way. When it happened it was a scorigami, the first 9-1 in league history.
That makes 9-1 the 28th most common final score out of 34 that have ever occurred in Euros. One point away, 10-1 has happened never and 9-2 has happened never.