Sure. Go to
www.redmondpie.com to my understanding they still offer signed versions. Find your device then download the corresponding iOS 8.4.1 restore zipfile & save it to your pc.
Rename the saved/downloaded zipfile extension to .ipsw instead of .zip (just highlight .zip & rename it to .ipsw) now go to iTunes click on your iPad & click the Restore button. When asked, go to the folder your renamed iOS 8.4.1 Restore.ipsw file is & iTunes will install it.
REMEMBER to turn off auto updates on your iPad! Otherwise it will auto update the iOS 9+ version again!
In your DJI GoApp go to your HD icon & click the Custom button. Look at your channels & find the LOWEST one between 2 that show high interference. Choose that low channel. You should be flying with no issues.