oK heres the thing, i have a 4 month old dog puppy and im thinking of rehoming an 8/9 month old  bitch puppy, now could this work, if i spent alot of time individually training them???

That would depend on the breed and the individual puppies temperament. You would also probably find that that as they are both pups they will bond together and learn to depend on each other, which might not be the best thing for you as they will need training. This is why most reputable breeders will not sell two puppies together.

It could work but you will also very shortly have the problem of the bitch pup coming into season and your boy pups could already mate with her and sire a litter. 

This will then continue to be an issue unless you plan to have one neutered.  

Bear in mind that neutering is not without it's drawbacks and will affect developement in both sexes if performed before physical and mental maturity.

Puppies learn a huge deal from their mother and other adults in the household. Adolescent dogs do not have the appropriate 'doggie manners' at that stage to teach your pup good manners and your pup may end up learning inappropriate adolescent traits and manners.

You are much better off spending the time bonding and training your puppy and wait until he is 2 years old and has acquired proper doggie manners (both with dogs and humans) before you think about getting another dog.

Ofcourse, if you decide to go ahead, then I am sure you can work around the issues, but you will be making life a lot harder for yourself than need be.

All the best,
Patty

This could work if you take care with seasons, the dog could start to do things like ent mark as he gets older, not all dogs do it though.
Fiona