My daughter has no real certs at all but luckily, she was accepted by all DSS and private schools we have attent for interview. So I guess the schools care about the interview more.
Dont' worry too much to prepare the cert! Relax! :)
Letting your child participate in competitions is good for his/her development. Having an award is already worth much appreciation from you. IT's good to have a top prize, but even if it is a participation cert., it still shows that you as a parent are willing to expose your child in different aspects and thus your method of developing your child can be seen.