There aren't any specific GCSEs you need to pick to become a professional athlete.
My advice would be to pick PE and/or sport studies, depending on what your school offers.
Food technology might be useful in terms of learning about nutrition, child development could help if you're also thinking about the possibility of going into coaching, psychology could help with the principles of sport psychology and doing triple science would mean more biology content, but absolutely none of these are necessary.
Potentially a long shot, but GCSE dance would involve spending more time doing physical exercise. Dance exercises such as ballet can be useful for building strength and flexibility, which would be useful as a footballer.
Overall, there isn't anything you have to pick. The main thing is that you pick subjects you enjoy. If you happen to not particularly enjoy school at the moment, picking subjects with some link to sport could make GCSEs feel like a positive step in the right direction.