I have a Drupal 7 site that was not built with composer. I have been using Drush 7 with it, but about a week ago, wd-show --tail stopped working, I'm not getting any output. I installed Drush 9, but am having difficulty configuring it. 

I created an xml file, per the example, Instructions say to put aliases in $PROJECT/drush/sites/self.site.yml but I don't have a project root with composer.json ---- can I get this to work without using composer to build my site? Or is drush 9 depending on the drupal site using composer?

I'm running the local version of the site in MAMP on my Mac. I created sites/drush/sites/self.site.yml -- it contains:
local:
  root: /Users/pglatz/dev/wdocs/wdocs-code/www
  uri: 'https://www.whiskerdocs-local-qa.pglatz.com/'


The command I'm using is:
drush9 @local --alias-path=/Users/pglatz/dev/wdocs/wdocs-code/www/sites/drush/sites --root=/Users/pglatz/dev/wdocs/wdocs-code/www

When I run it, I get the error:
Command wd-show was not found. Pass --root or a @siteAlias in order to run Drupal-specific commands.

But I am passing --root and a site alias. Likely a dumb syntax error on my part, but I can't figure it out. Thanks for your help.