Remove Python 3.9 support ahead of PyTorch 2.9 in v0.11.1 (#26416)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

docs/contributing/README.md

@@ -54,7 +54,7 @@ For more details about installing from source and installing for other hardware,
 For an optimized workflow when iterating on C++/CUDA kernels, see the [Incremental Compilation Workflow](./incremental_build.md) for recommendations.
 
 !!! tip
-    vLLM is compatible with Python versions 3.9 to 3.12. However, vLLM's default [Dockerfile](gh-file:docker/Dockerfile) ships with Python 3.12 and tests in CI (except `mypy`) are run with Python 3.12.
+    vLLM is compatible with Python versions 3.10 to 3.13. However, vLLM's default [Dockerfile](gh-file:docker/Dockerfile) ships with Python 3.12 and tests in CI (except `mypy`) are run with Python 3.12.
 
     Therefore, we recommend developing with Python 3.12 to minimise the chance of your local environment clashing with our CI environment.
 
@@ -83,7 +83,7 @@ vLLM's `pre-commit` hooks will now run automatically every time you commit.
 
     ```bash
     pre-commit run --hook-stage manual markdownlint
-    pre-commit run --hook-stage manual mypy-3.9
+    pre-commit run --hook-stage manual mypy-3.10
     ```
 
 ### Documentation

docs/getting_started/installation/cpu.md

@@ -20,7 +20,7 @@ vLLM is a Python library that supports the following CPU variants. Select your C
 
 ## Requirements
 
-- Python: 3.9 -- 3.12
+- Python: 3.10 -- 3.13
 
 === "Intel/AMD x86"
 

docs/getting_started/installation/gpu.md

@@ -17,7 +17,7 @@ vLLM is a Python library that supports the following GPU variants. Select your G
 ## Requirements
 
 - OS: Linux
-- Python: 3.9 -- 3.12
+- Python: 3.10 -- 3.13
 
 !!! note
     vLLM does not support Windows natively. To run vLLM on Windows, you can use the Windows Subsystem for Linux (WSL) with a compatible Linux distribution, or use some community-maintained forks, e.g. [https://github.com/SystemPanic/vllm-windows](https://github.com/SystemPanic/vllm-windows).

docs/getting_started/quickstart.md

@@ -8,7 +8,7 @@ This guide will help you quickly get started with vLLM to perform:
 ## Prerequisites
 
 - OS: Linux
-- Python: 3.9 -- 3.13
+- Python: 3.10 -- 3.13
 
 ## Installation