adjusts Python versioning again

Author: chalmerlowe

noxfile.py

@@ -35,7 +35,6 @@
 DEFAULT_PYTHON_VERSION = "3.14"
 
 UNIT_TEST_PYTHON_VERSIONS: List[str] = [
-    "3.9",
     "3.10",
     "3.11",
     "3.12",

owlbot.py

@@ -27,9 +27,9 @@
 # Add templated files
 # ----------------------------------------------------------------------------
 templated_files = common.py_library(
-    unit_test_python_versions=["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"],
-    system_test_python_versions=["3.9", "3.14"],
-    default_python_version="3.13",
+    unit_test_python_versions=["3.10", "3.11", "3.12", "3.13", "3.14"],
+    system_test_python_versions=["3.10", "3.14"],
+    default_python_version="3.14",
     cov_level=98,
     intersphinx_dependencies={
         "pandas": "https://pandas.pydata.org/pandas-docs/stable/"