GA v1.9 in docs (#6626)

## What are you changing in this pull request and why?

Updates docs for v1.9 GA


## Checklist
- [ ] I have reviewed the [Content style
guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
so my content adheres to these guidelines.
- [ ] The topic I'm writing about is for specific dbt version(s) and I
have versioned it according to the [version a whole
page](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#adding-a-new-version)
and/or [version a block of
content](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#versioning-blocks-of-content)
guidelines.
- [ ] I have added checklist item(s) to this list for anything anything
that needs to happen before this PR is merged, such as "needs technical
review" or "change base branch."
- [ ] The content in this PR requires a dbt release note, so I added one
to the [release notes
page](https://docs.getdbt.com/docs/dbt-versions/dbt-cloud-release-notes).
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ADDING OR REMOVING PAGES (if so, uncomment):
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website/dbt-versions.js

@@ -20,6 +20,7 @@ exports.versions = [
   },
   {
     version: "1.9",
+    EOLDate: "2025-12-08",
   },
   {
     version: "1.8",

website/snippets/core-versions-table.md

@@ -2,8 +2,8 @@
 
 |                      dbt Core                                 | Initial release |      Support level and end date      |
 |:-------------------------------------------------------------:|:---------------:|:-------------------------------------:|
-| [**v1.9**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.9) | Release candidate | TBA |
-| [**v1.8**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.8) | May 9 2024    | <b>Active Support &mdash; May 8, 2025</b>|
+| [**v1.9**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.9) | Dec 9, 2024  | <b> Active Support &mdash; Dec 8, 2025</b>|
+| [**v1.8**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.8) | May 9, 2024   | <b>Active Support &mdash; May 8, 2025</b>|
 | [**v1.7**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.7) | Nov 2, 2023   | <div align="left">**dbt Core and dbt Cloud Developer & Team customers:** End of Life <br /> **dbt Cloud Enterprise customers:** Critical Support until further notice <sup>1</sup></div> | 
 | [**v1.6**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.6) | Jul 31, 2023  | End of Life ⚠️ |  
 | [**v1.5**](/docs/dbt-versions/core-upgrade/upgrading-to-v1.5) | Apr 27, 2023  | End of Life ⚠️ |