One problem related to brake disc caliper has been reported for the 2009 Jeep Wrangler. The most recently reported issues are listed below.
My daughters 2009 Jeep wagoneer x which she has owned new since may had the right front brake caliper fall offwhile she was operating the vehicle. She was driving at 25mph when this happened (thank goodness). The font wheel locked up and made the back of the Jeep to come up off the ground. When the tow truck driver arrived he stated that this was the second one he had to come after for the same problem. Currently the only maintenance that this Jeep has had is normal service of the engine( oil changes).