Chile sets on one of the most active subduction zones in the world. As such, it can and does get quakes exceeding 9. Here in the States, we have one two areas with that kind of quakes. Alaska, and the Pacific Northwest.
The last time a 9+ quake let go in Alaska was on Good Friday, 1964, and Anchorage was devestated.
The last time the Pacific Northwest Subduction Zone let go, it was a 9.5, and in the Straight of Juan de Fuca, put driftwood 500 ft up hillsides. That was on January 29, 1700, if I am remembering the date correctly. From the evidence, the quake let go from the junction off Cape Mendecino, to the North end of Vancouver Island.
But that is still not the most dangerous quake zone for the US. Were the New Madrid quakes happen today as they did in 1812, the damage would be in the trillions of dollars. And we would be in need of other nations help in initial search are rescue efforts.