Def take him to the vet and get the urinalysis done, he might have a UTI. Snickers had one and he couldn't help but go everywhere, even on his way to the door to let me know, he would squat and pee b/c he had to and had a UTI. If that is ruled out, then it is his instinct to mark. Is he lifting his leg??
Also, as for the crate situation, is there anyone that can come home for lunch and let him out?? Thankfully my husband is able to and has been doing it for the past 2.5 yrs since we got our 1st yorkie Snickers and it helps a TON with the potty training and teaching them to only go outside. I know many people cannot come home in the middle of the day, and if you can't--I highly recommend the potty pads, they just can't hold it.
Viv