Re-drop support for Python 3.9

[NotAussie]

Cloudstile will only support non-EoL Python versions, with an upcoming update 3.9 will be partially supported until October, this issue therefore will be open until October when support will be dropped.

[NotAussie]

/remind me to drop Python 3.9 on Oct 1

[github-actions]

@NotAussie set a reminder for 2025-10-01

[github-actions]

👋 @NotAussie, drop Python 3.9

[NotAussie]

Issue will be completed by Jan 31, 2026!

[NotAussie]

Fixed in e459c75.