Absolutely not since any crime can be forgiven by God.So if a Saint is found guilty in crimes, etc then his sainthood would be removed from him?
The question isn’t if the saint was 100% holy during their entire life, but if they were holy and bound for heaven at the end of their life here on earth.
The process of canonization is a process of a discernment to see if the person being considered is worthy of canonization, to discern if the person is now indeed in heaven. Hence, why at least one miracle (and usually two miracles) due to the person’s intercession is usually required for sainthood.
God knows better than what anyone of us will ever know about what Saint Pope John Paul II knew and did not, what he did and did not do. So when God signaled to us here on Earth that Saint Pope John Paul II is indeed in heaven by the two miracles ascribed to Saint Pope John Paul II intercession, then we can be assured that Saint Pope John Paul II is indeed in heaven and able to intercede on our behalf.