Congrats on the job!! I read a lot of occupational folklore articles on cabbies

Also, my dad drove cabs. ^^
First of all, try to gradually up the time Blitzen is left alone. Start at 5 mins and go from there increasing the time so he knows you will always return. NEVER give him goodbyes and dramatic pets and kisses telling him how much you'll miss him and stuff because he will transfer that energy into anxiety. Always make the departure nothing exciting. It usually helps to get ready and then relax and go about normal activities too, like- put on your coat and grab your keys or whtever but then go sit down and watch a bit of tv until he calms down. Ingore him completely about 5-15 minutes before you leave. This includes patting, talking to or feeding him so make sure you leave down water in plenty of time.
I guess you could give the kong as you leave?? I always had a dog who got so nervous as we left that he knew once fresh deli hams and cheese came out that he would be alone and you'd be surprised- Coco never once touched the deli slices until someone returned!!!

So I don't know when an appropriate time would be for the kong. You don't want him to eat everything up before you leave while he's being ignored....
Anyway, Coco is 13 and while he can be left alone for this period of time we HAVE to keep him in a diaper with a maxi pad. He pees in it everyday while out of anxiety or necessity it's unclear now. But you could do the same for Blitzen if he's still too young to hold it fr hours.
Mostly, this big change will affect him. Dogs live socially and once their pack leaves he will naturally get nervous. Is he crate trained? Or room trained? (I cannot blockade Coco personally bc it makes him worse). It would be better to confine Blitzen to one room where there is a window. Any damage will be confined to that area as well. Training is a big must-do here, lifestyle changes sometimes make slow training inmpractical but overtime he will get used to the routine.
Also, do not make a scene once you return home. I know you will have missed your dog and he would have missed you but its very important not to excite him. Make it a routine to come home walk past him and ONLY greet him once he is calm. If he learns that he gets attention if he jumps on you and gets too excited and if you give in and pet him and squeal or over-dramatize your reunion then he will always associate being alone with a nervous energy that you bring home. He will not be able to contain his excitement and it will be way harder to break the system... Trust me, I'm STILL undoing 9 or 10 years of this on Coco. -_-
You can leave a light on if you like, he might not care. It's more for you than him since dogs can see plenty fine in the dark. Admittedly, I always leave a light on if I know I will be gone while it gets dark. Coco's got cataracts though and the light serves him in his lonliness so at least he can see where he's going!! lol
Anyway, good luck!! Let us know how he's taking it!