[Nancy1999]

When you trained him to use the bell and go outside, did you reward him? Sometimes, people think that once a dog learns something they don't have to reward them anymore, it's good to continue the rewards though. Not every time, but you should vary how the rewards are given, like every 5th time, and then every 2nd time then every 9th time etc. Don't punish ever for mistakes, ignore the mistakes and reward the success. Nine months is a little young to be fully trained for a Yorkie. Is he neutered? Are you sure he isn't marking? Marking is different than peeing and has nothing to do with a full bladder. An unneutered male feels compelled to mark his territory. If he isn't neutered, you should get him neutered ASAP before marking becomes an established habit.