Hi,
Your GCSEs are great. I just want to add that whilst you may only have a score of 24 out of 27 and previously cutoffs have been higher, remember that the proportion of people achieving a grade 9 is lower than those previously achieving an A* grade. It’s likely that the cutoff point will be lower as many people who previously would have got 3 points from an A* in their English and maths would now only get 2 for an 8. I would still be weary of applying with anything lower than 25 and would consider other options but, if you absolutely love Cardiff, then it’s something to think about.
Good luck :-)