For days now my Facebook app keeps saying waiting

I assume that you were trying to update the app and got into this predicament. Is that correct?

If it is, did you try tapping on the app icon to see if the download would pause, then tap it again to see if the download would resume?

Did you try rebooting? Reboot the iPad by holding down on the sleep and home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider if it appears on the screen - let go of the buttons. Let the iPad start up.

How about deleting the app from the settings app? Settings>General>Usage>Storage>Show all apps. Find the Facebook app, tap the arrow next to it and delete it in the next screen.

My fb messanger icon button is darkened and says waiting ...can not open my messanger