[SPARK-50121][INFRA] Add Python 3.9 Daily Python GitHub Action job

### What changes were proposed in this pull request?

This PR aims to add `Python 3.9` Daily Python GitHub Action job.

### Why are the changes needed?

Previously, this is covered by PyPy3.9 GitHub Action job, but now it's moved to PyPy3.10 GitHub Action job.

According to Python Versioning Policy, https://devguide.python.org/versions/, we need to maintain it until October 2025.

### Does this PR introduce _any_ user-facing change?

No, this is an infra-only change.

### How was this patch tested?

Manual review.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes apache#48659 from dongjoon-hyun/SPARK-50121.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: yangjie01 <yangjie01@baidu.com>

.github/workflows/build_python_3.9.yml

@@ -0,0 +1,45 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+name: "Build / Python-only (master, Python 3.9)"
+
+on:
+  schedule:
+    - cron: '0 21 * * *'
+
+jobs:
+  run-build:
+    permissions:
+      packages: write
+    name: Run
+    uses: ./.github/workflows/build_and_test.yml
+    if: github.repository == 'apache/spark'
+    with:
+      java: 17
+      branch: master
+      hadoop: hadoop3
+      envs: >-
+        {
+          "PYTHON_TO_TEST": "python3.9"
+        }
+      jobs: >-
+        {
+          "pyspark": "true",
+          "pyspark-pandas": "true"
+        }