iPad iOS 9.3.5 and Google Photos/Drive dilemma

Has anyone resolved the issue of not being able to install Google Photos or Google Drive on an older iPad running 9.3.5 where the iOS version cannot be updated to 10 or more? I have an older iPad that is running out of space as I have many photos and videos. While these are backed up to iCloud, and the backup settings storage optimized, this is not a long-term solution as I cannot ONLY keep the files in iCloud without a copy on the iPad. I would like to be able to use Google Photos &/or Drive so as to move all these files into the cloud. However, I am unable to install either Google Photos or Google Drive (both of which require at least iOS 10), or to update past iOS 9.3.5. Any suggestions? Help!!!