Chesapeake Bay Retriever? Can you give me information about these dogs as I am wanting to get a male puppy, about 8 months old soon.?

You clearly are not serious about the poor dogs health since they are WORKING breeds and make for very, very poor service dogs. 

And Chrones is not a disability so there's no way any one who has it can have a service dog since all it is inflammatory bowel disease 

They are used by some. However, I cant see how a service dog could help chrons

The best way to get familiar with this breed is to do lots of research on it. Know the breed inside & out. Read everything you can find on the breed. Lots of information online, there are hundreds of books on dogs & their training. Books specific to each breed, There is no way I can give you all the information on the sites I found. Just no way.

I have never seen one except in pictures.

I am not going to research it for you.

Crohn's disease is an inflamitory bowel disease...  It does not qualify you for a service dog.  The disease does not prevent you from functioning independently.   There's nothing a dog could do for you.

I would imagine a chessie would be very similar to a lab or a golden, since they were bred for similar purposes.

https://dogtime.com/dog-breeds/chesapeake-bay-retr...

There are other websites.    But why not locate a reputable knowledgeable breeder, via the relevant Breed Club and talk to them.   This isn't a very 'common' breed however so you may find breeder/owners few and far between.  

I'd suggest that 8 months could be a difficult age with the onset of puberty.  Plus what has been going on with the youngster up to now?