fix: cleanup of 3.9 removal and preparation for 3.14

[Lulalaby]

WIP

Depends on #2948

[pycord-app[bot]]

Thanks for opening this pull request! Please make sure you have read the Contributing Guidelines and Code of Conduct.

This pull request can be checked-out with:

git fetch origin pull/2988/head:pr-2988
git checkout pr-2988

This pull request can be installed with:

pip install git+https://github.com/Pycord-Development/pycord@refs/pull/2988/head

[Copilot]

@Lulalaby I've opened a new pull request, #2989, to work on those changes. Once the pull request is ready, I'll request review from you.