ok, so I have been just awarded a 3rd class degree classification with honours in Graphic Design and Illustration and I really wanted to pursue a MA or get a good job.

However, I do posses another 3 certifications from fine art and design courses from the Open University, one on modern art from MoMA New York and another from University of Melbourne.
Additionally, I am the winner of a 2 weeks work placement at BBC Worldwide London (that I just finished and received a letter of recommandation from the BBC's Creative Director) and I was just informed that I also won a 3 month internship at a creative studio in London that works with huge brands.
I also have another year of experience from my first graphic design job at a small agency and I am also a Mentor on the educational platform Coursera on a fine art course and worked briefly as an Adobe CC Rep while at university.

My question is: are my experience and my certifications enough for a future employer to ignore my 3rd class degree?
And going even further, is it enough for me to possible get into a MA course?

And how important is the degree classification in the creative industries?

It's possible, but of course harder. I don't know specifically about creative industries. I would suggest networking to find a way in if possible, as it will be easier to overlook a 3rd on paper than if someone knows you.

It's all about your portfolio (in my experience).
If you're work is solid, employers won't care.

So far as I know in the creative industries, one is not much fussed with degrees.