Update Go version to 1.25.9
## Summary
Go 1.25.9 has been released.
## Process
- [x] :loudspeaker: Consult the [GitLab Go Upgrade Process](https://docs.gitlab.com/ee/development/go_guide/go_upgrade.html#upgrade-process).
- [x] :loudspeaker: Check the upstream release notes and set this epic's due date.
- [x] :loudspeaker: Please follow and track all work [per the established process](https://docs.gitlab.com/ee/development/go_guide/go_upgrade.html#tracking-work).
- [x] :loudspeaker: Ensure version alignment with [Go FIPS](https://github.com/golang-fips/go) for GitLab and GitLab runner.
## Resources
- [The GitLab Go Upgrade Process](https://docs.gitlab.com/ee/development/go_guide/go_upgrade.html#upgrade-process)
- [Go source code](https://go.dev/dl/)
## Builders / Images
These must be upgraded first before subscriber projects can start their development.
| Status | Builder / Image |
|----------------|----------------------------------------------------------------------------------------------------------------|
| :construction: | [GitLab Build Images](https://gitlab.com/gitlab-org/gitlab-build-images) |
| :construction: | [GitLab Developer Kit](https://gitlab.com/gitlab-org/gitlab-development-kit) |
## Components
```glql
display: table
title: Open Issues related to the Go 1.25.5 upgrade
fields: title, state, labels("group::*") AS "Group", assignee
limit: 50
query: epic = &21754 AND state = opened
```
```glql
display: table
title: Closed Issues related to the Go 1.25.5 upgrade
fields: title, state, labels("group::*") AS "Group", assignee
limit: 50
query: epic = &21754 AND state = closed
```
## Release Readiness
| Status | Component Name |
|----------------|----------------------------------------------------------------------------------------------------------------|
| :construction: | [GitLab Omnibus Builder](https://gitlab.com/gitlab-org/gitlab-omnibus-builder) |
| :construction: | [Cloud Native GitLab](https://gitlab.com/gitlab-org/build/CNG) |
epic