The 9th String Quartet was written in Rio in 1945, and dedicated to Mindinha.
Movements:
String Quartet
Published by Southern Music Publishers, New York.
You can listen to the Quarteto Amazonia playing Quartets 8, 9, & 10, streamed on the Internet on this page of the Radio UOL website.
The premiere was in London in 1947.
There are two records in the Villa-Lobos Concerts database for this String Quartet as of August 2009.