Welcome to YT and congrats on your new little one!
8 weeks is very young for a new Yorkie pup to be in his new forever home.
Most reputable breeders agree that the proper age of placement is 12 weeks. Because of that, I would strongly suggest that you monitor him closely during his first few weeks there and make sure that he is eating several times a day. Also, make sure he is getting enough rest. Familiarize yourself with the warning signs of hypoglaucemia and make sure you have Nutrical on hand. It is very easy for these little ones--especially at such a young age--to have issues with this and it can hit them VERY quickly.
Crate training, like any training, takes time...months even. Just be patient and persistant and he'll get the hang of it soon. He's a little pup so it will be hard on him for a while...which will make it hard on you too.
Hang in there!