iPad mini will not install app

That is because many third party app developers have moved on from supporting 6, 7, 8 and 9-year old iOS devices and older iOS versions and have removed all older versions of their apps from the Apple iOS App Store servers, now.

There maybe no way to get older versions of many popular apps, for older iOS devices, any longer.

Sorry. It is what it is at this very late date.

If you need an iPad that can run the latest and greatest versions of iOS, as well as, the most current apps available, then, you will need to purchase a new iPad from Apple or a discounted, refurbished iPad from Apple’s Refurbished & Clearance section of Apple’s Website.

Best of Luck to You!

For any new apps that have moved on to iOS 11 and newer, you will no longer be able to download these apps, initially, from the iOS App Store, any longer.

You will need to purchase a new or discounted, refurbished iPad from Apple.

For any apps that were already installed on that iPad, you can redownload these apps by launching the iOS App Store app and tapping the Purchased option in the lower App Store app menu and redownload all of your previously installed apps from the Purchases option/section of the iOS App Store app.

Best of Luck to You!