Do you have a direct link? I tried finding it in the Play Store on my 12.2 and it doesn't show up as if it isn't available for the tablet.
1) here is a link to app store:
https://play.google.com/store/apps/details?id=com.microsoft.office.officehub&hl=en
2) Use this link to download it to your computer (it can be used to download any free app that is not allowed on your tablet):
APK Downloader [Latest] Download Directly | Chrome Extension v3 (Evozi Official)
3) Insert the link from step 1 to the "package ..... url" field in the link from step 2. Click on the generate Url button(blue button) and den the download button (green button)
4) copy the downloaded .apk to your 12.2 or to dropbox and install it from there. You have to allow packages from unknown sources in the security settings of your tab.
5) have fun.
I hope this helps.