Still trying to use Gmail on ios 9 ipad.

Millions of people use the Apple Mail app to send and receive gmail on iPad and iPhone. There is simply no basis for Google to say the Apple Mail app is not secure.

Since you can't download the gmail App on your iPad because it is too old and not able to use the newer 64 bit iOS levels, then your choices are use the Apple Mail app or don't get gmail on your iPad. Or buy a newer iPad capable of running the 64 bit IOS versions.

You should not use the Safari Browser on such an outdated device however. This link provides recommendation on Web Browsers which may still be compatible with an old iPad.

Downloading Older iOS 9.3.5 Versions of A… - Apple Community

I'm not a gmail user, so perhaps someone who is will chime in with better advice.

That's great. I'm glad to see this!

This can happen from any site, anywhere. It does not mean Apple's Mail App is any less secure than any place you could sign into your gmail account.