Does Duolingo Plus follow the Duolingo account or the Google account on Android?
My biggest concern about signing up for Duolingo Plus is getting the purchase wrong and having it tied to something I don't expect. It seems I make the purchase with my Google account, so does Plus then follow that Google account on the phone? Or does it get tied to the Duolingo account? As in, if I use my phone to log into a different Duolingo account, will I still get Duolingo Plus? Or if I log into my Duolingo account on another phone with a different Google account, will I have Duolingo Plus then?
I cannot be 100% positive as I use iOS devices, but I imagine that Duo are just using the Google account to collect your subscription on behalf of Duo. It should not affect which device you can use the Plus subscription on, except of course the capabilities of the subscription are probably tied in with Android devices only so if you use Duo on an iPhone for example, it would not give you the same Plus functionality as on an Android phone.
Since you're asking for help using the site, could you move this post to the Troubleshooting forum? Your post is likely to get a lot more attention there, because that's where the people who are willing to help with this sort of problem hang out. It will also help keep this forum easy to navigate for those who aren't part of the troubleshooting group.
Don't delete it and create a new one, just click edit, and change the topic from Duolingo to Troubleshooting. Here's a guide on how to move a post: https://www.duolingo.com/comment/16609773.
...and here's a guide on how to choose which forum to post in: [Guide] In which forum should I post my discussion?.