Despite the smiles and reassuring chats to herself before the run up, McCartney failed all three attempts at 4.65 metres.
The 20-year-old lay on her back for a few moments as she realised her campaign was done, before hopping up, smiling and waving to her supporters.
"I put everything out there. I don't really know what went wrong. I need to look at the video," McCartney said following the final.
"On the final attempt I put everything into it and blew through, which means that the pole was too soft and there's no way I could have jumped it. So it's kind of a good thing. It means I jumped well but I had the wrong pole."
"So there's some good things but it's a random place to come ninth."
McCartney was said it was a good experience despite the result.
"This my first world champs. I'm still really young, I'm still learning a lot and I'm not scared to fail because I know that I have a lot to learn from these sorts of things if I'm hopefully going to have a long career ahead of me still. Every opportunity I have to compete in front of these large stadiums and crowds is really really good."
It's been a tough maiden World Champs for McCartney, who's spent much of the past month recovering from her well documented Achilles injury.
She eased up in training and missed meets to try and get things right for London.
The rust showed in qualifying when she jumped a sub-par 4.50m, which luckily, was good enough to progress to the final.
Charlie Bristow traveled to London courtesy of Air New Zealand.
