The test from JCK-runtime suite fails in case of compilation mode for any VM (-Xcom).

For mixed mode and interpreter mode the test passes. See logs:

user@host:/export/local/sk$ ./jdk9_120_p1/bin/java -Xcomp -showversion NewTestCase
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+120)
Java HotSpot(TM) Minimal VM (build 9-ea+120, compiled mode)

method setIndex(int) return incorrect char
  returned char is f
  expected char is t
public void setIndex(int index)
user@host:/export/local/sk$ ./jdk9_120_p1/bin/java -Xint -minimal -showversion NewTestCase
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+120)
Java HotSpot(TM) Minimal VM (build 9-ea+120, interpreted mode)

OKAY
user@host:/export/local/sk$ ./jdk9_120_p1/bin/java -Xmixed -minimal -showversion NewTestCase
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+120)
Java HotSpot(TM) Minimal VM (build 9-ea+120, mixed mode)

OKAY