[Doc] Update 0.9.0rc1 release date

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

Author: wangxiyuan

docs/source/developer_guide/versioning_policy.md

@@ -34,7 +34,7 @@ Following is the Release Compatibility Matrix for vLLM Ascend Plugin:
 
 | Date       | Event                                     |
 |------------|-------------------------------------------|
-| 2025.06.07 | Release candidates, v0.9.0rc1             |
+| 2025.06.09 | Release candidates, v0.9.0rc1             |
 | 2025.05.29 | v0.7.x post release, v0.7.3.post1         |
 | 2025.05.08 | v0.7.x Final release, v0.7.3              |
 | 2025.05.06 | Release candidates, v0.8.5rc1             |

docs/source/user_guide/release_notes.md

@@ -1,6 +1,6 @@
 # Release note
 
-## v0.9.0rc1 - 2025.06.07
+## v0.9.0rc1 - 2025.06.09
 
 This is the 1st release candidate of v0.9.0 for vllm-ascend. Please follow the [official doc](https://vllm-ascend.readthedocs.io/en/) to start the journey. From this release, V1 Engine is recommended to use. The code of V0 Engine is frozen and will not be maintained any more. Please set environment `VLLM_USE_V1=1` to enable V1 Engine.