Add testing for Bazel 9 to `@rules_java` CI

Also switch from using fixed versions with latest release for each major version.

PiperOrigin-RevId: 865968441
Change-Id: I9809f82cd9e6ece901b1cd7a4e5754b17196581d

.bazelci/presubmit.yml

diff --git a/.bazelci/presubmit.yml b/.bazelci/presubmit.yml
index 4fe6a43..30c6393 100644
--- a/.bazelci/presubmit.yml
+++ b/.bazelci/presubmit.yml
@@ -34,8 +34,8 @@
 
 matrix:
   all_platforms: ["rockylinux8_arm64", "ubuntu2004", "macos", "macos_arm64", "windows"]
-  bazel: ["7.7.1", "8.4.2", "last_green"]
-  modern_bazel: ["last_green", "rolling"] # Fully supported Bazel versions
+  bazel: ["7.x", "8.x", "9.x", "last_green"]
+  modern_bazel: ["9.x", "last_green", "rolling"] # Fully supported Bazel versions
 
 tasks:
 # Bazel 9+
@@ -47,8 +47,8 @@
     test_targets: *test_targets
 # Bazel 8.x
   build_and_test_bazel8:
-    name: "Bazel 8.4.2"
-    bazel: "8.4.2"
+    name: "Bazel 8.x"
+    bazel: "8.x"
     platform: ${{ all_platforms }}
     build_targets: *build_targets
     test_targets: *test_targets
@@ -56,8 +56,8 @@
     - "--test_tag_filters=-min_bazel_9"
 # Bazel 7.x
   build_and_test_bazel7:
-    name: "Bazel 7.7.1"
-    bazel: "7.7.1"
+    name: "Bazel 7.x"
+    bazel: "7.x"
     platform: ${{ all_platforms }}
     build_targets: *build_targets
     test_targets: *test_targets