Is the chord Aadd9 the same as Ab2?

I tried to look for an easy enough ab2 but they are all down the neck. I would need one that is the closest to the neck as possible. If not, can I use an Aadd9, or just a plain A to replace it. Will you be able to hear the difference? I'm trying to play "Here I am to Worship" by Tim Hughes in 3 flat. I know it's not the easiest key but I need to play it in that key. Help please!