Drupal 9?

I installed everything, got no error. But I do not see any emojies :(

Any suggestions how to fix this?

I don't know if their is a plan. But it shouldn't be too hard to upgrade. When you run the upgrade status against the module you only get 3 errors. Looks like the module is using libraries_get_path() which is removed in D9.

1.
web/modules/contrib/ckeditor_emojione/ckeditor_emojione.module on line 51
Call to deprecated function libraries_get_path(): Will be removed before a stable Drupal 8 release. Please use the new library load and managment concepts described at: https://www.drupal.org/node/2170763

2.
web/modules/contrib/ckeditor_emojione/src/Plugin/CKEditorPlugin/EmojioneCKEditorButton.php on line 59
Call to deprecated function libraries_get_path(): Will be removed before a stable Drupal 8 release. Please use the new library load and managment concepts described at: https://www.drupal.org/node/2170763

3. easy enough but 1 and 2 need to be fixed first.
web/modules/contrib/ckeditor_emojione/ckeditor_emojione.info.yml
Add core_version_requirement: ^8 || ^9 to designate that the module is compatible with Drupal 9. See https://drupal.org/node/3070687.

CKEditor Emoji uses the same library and stats compatible with D9. could look into switching modules or check their code for some examples.
https://www.drupal.org/project/emoji

Subscribing! I would like to have it soon for my new drupal 9 site I'm preparing.

I'm searching for a solution for days and the only d9 compatible module https://www.drupal.org/project/emoji requires too many dependent modules and I don't want to spam my site with so many of them.
Does this module here have the same requirements? Will it install the same dependent modules automatically in order to work or does it work independently?

Here's a patch containing the necessary changes.

Made a bit cleaner version based on feedback by @Dropa.

Thanks guys, patch pushed to dev branch!