This really depends on how your child’s English standard is. If it is good, then you will have less of a problem. But I believe that some of the schools still want to see his G8 transcript so it might not be that easy to skip a class to G9.
Yes your child will be too old. Schools do not want to see students that are that much older than their peers. You can be a few months old than 15 years old when you enter G9, but not too much more. However you should also ask the school about this when you apply as different schools have different requirements.
I recommend that you go to a less competitive US school this year to study G8. That way you can improve on the English more quickly than if your child stayed in China, even at an international school.
