Install Drush 9 with Composer

Ran this command (got no errors):

composer global require drush/drush:9.* 

Then cd to /var/www/site.com/htdocs/ and run drush status, it gives:

-bash: /usr/local/bin/drush: No such file or directory.

I can’t find any documentation covering this. Every documentation only has that first command to run and that’s it, no debugging, nothing.

Ubuntu 18.04, Drupal 8.