If you recently purchased or acquired this older iPad, there maybe a couple of ways to get older, compatible versions of apps.
Older versions of apps may still exist in the iOS App Store, despite the fact the apps may have moved on to an higher minimum iOS version, now.
If you need older versions of apps that have moved on toiOS 10 and later, tap on my link below and choose the method that best works with your current situation.
CAREFULLY read and follow ALL directions. Especially so for my computer/older iTunes procedures.
Any of my procedures/solutions work!
Downloading Older iOS 9.3.5 Versions of A… - Apple Community
A Disclaimer.
Apps may or may not have older iOS 9.3.5 versions still available from within the iOS App Store.
There are a couple of ways to try/attempt to get an older version of an app. Pick the method that works best for your situation/circumstances.
In addition, I would STOP using that nearly 3-year old Safari Web browser, as it is, probably, not safe and secure to use any
longer, and seek out a third party web browser that is STILL currently being updated and STILL being supported on iOS 9.3.5.
Heed my advice on this issue in my above link.
Good Luck to You!