Predicted results in the IB are absolutely valid and serve as the basis for many admissions decisions.
I am not sure the same is true with the IGCSE. Especially when the IGCSE was completed long before applications were being sent to colleges (that timing issue is why the IB has to issue predicted grades).
My take on this is that the school in which he completed 11th and 12th should report those grades and the school in which he completed 9th and 10th should report those grades. Lots of kids don’t have a GPA to show and colleges manage to make admissions decisions just fine for them.