If you have a newer iDevice with newer iOS that is attached to your Apple ID and password, you could install recent app to that device, then go back to your iPad 3 and attempt to download the recent app and see if iOS throws up a pop-up message telling you and older, compatible version of the app is available for your device and would you like to download and install this now?
Then tap the OK button at the end of the prompt.
If f you have a computer already running an older version of iTunes (version 12.6.3 or earlier ), you can try downloading the recent app/s, by accessing the iOS App Store, through iTunes, using your Apple ID and passord, and then, download the recent version of the app/s you like to use on your iPad, to iTunes on your computer, first.
Then, back on your iPad, you can try to download the latest app from the iOS App Store and if the developer/s has/have left an older, compatible version of their app/s on Apple's app servers, then you will receive a small window pop-up prompt that states that there is an older version of the app that is compatible with your device.. Would you like to download this version now.
Tap the OK button just below the prompt.
I would STOP using that 2-2-1/2 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.
Here are a few third party web browsers that I know are STILL being updated and supported on iOS 9.
Perfect Web browser
Dolphin Web browser
iCab Mobile Web browser
Aloha Web browser
Maven Web Browser
Opera Web browser
Maxthon Web browser
Good Luck to You!