Composer install of Calendar Module - DRUPAL 9

Is it possible to install Module using Composer in Drupal 9.
I have tried multiple ways and using the require 8.x-1.0-alpha4
But nothing I try allows installation this way.

ie

$ composer require "drupal/calendar"


  [InvalidArgumentException]
  Could not find a version of package drupal/calendar matching your minimum-s
  tability (stable). Require it with an explicit version constraint allowing
  its desired stability.


require [--dev] [--dry-run] [--prefer-source] [--prefer-dist] [--fixed] [--no-suggest] [--no-progress] [--no-update] [--no-install] [--no-scripts] [--update-no-dev] [-w|--update-with-dependencies] [-W|--update-with-all-dependencies] [--with-dependencies] [--with-all-dependencies] [--ignore-platform-req IGNORE-PLATFORM-REQ] [--ignore-platform-reqs] [--prefer-stable] [--prefer-lowest] [--sort-packages] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--apcu-autoloader] [--apcu-autoloader-prefix APCU-AUTOLOADER-PREFIX] [--] [<packages>]...

and

$ composer require "drupal/calendar:^8.x-1.0-alpha4"


  [UnexpectedValueException]
  Could not parse version constraint ^8.x-1.0-alpha4: Invalid version string
  "^8.x-1.0-alpha4"


require [--dev] [--dry-run] [--prefer-source] [--prefer-dist] [--fixed] [--no-suggest] [--no-progress] [--no-update] [--no-install] [--no-scripts] [--update-no-dev] [-w|--update-with-dependencies] [-W|--update-with-all-dependencies] [--with-dependencies] [--with-all-dependencies] [--ignore-platform-req IGNORE-PLATFORM-REQ] [--ignore-platform-reqs] [--prefer-stable] [--prefer-lowest] [--sort-packages] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--apcu-autoloader] [--apcu-autoloader-prefix APCU-AUTOLOADER-PREFIX] [--] [<packages>]...

I assume that therefore you do NOT support Composer installs?