"It's me" is how native speakers talk. But if we add a relative clause, I agree with Ben that "It is I who am waiting for you" is more probable in writing. But I already posted a longish answer on the other post that asks the same question. ;)
2015年7月28日
0
0
0
Adrian is right and wise.
2015年7月28日
0
0
0
Thank you Adrian!
2015年7月28日
0
0
0
Ben is correct, but if you say this in conversation, people will 'raise an eyebrow' because it sounds too formal.
Most people would say 'It is me [OR ' It's me' ] waiting for you'.