I’m unable to update my software because it saying I don’t have enough space but I do

The tags appended to your post are contradictory. iPad Pro with iOS9 isn’t possible.

If you are having difficulties with updating your iPad, this support page may be helpful with troubleshooting the problem:

If your iPhone, iPad or iPod touch won’t update - Apple Support

Are you really running iOS 9?

Exactly which iOS version do you have?

Exactly how much empty space do you have?

And, what is the size/space requirement for whatever you are trying to download?

Is it an app, a new iOS version or ??