This is one for puppy experts.  Compared with the others in the litter one at 9 weeks has 'piggy eyes'.  The rest have wide open big brown eyes.  Would you see this as a problem?  Eye sight is fine.

Depends on the breed and therefore what shape and set the eyes should have - but as all the other pups are different then one supposes that the one with 'different' eyes has a problem either with the eyes or with the conformation. Sorry but the question is far too wide to answer, if you know or have studied the breed then you will know what the eyes of a nine week puppy should be like and if they are not typical or to type then I would guess there is a problem although if you do not intend to breed or show it will not matter providing it is not the sign of an underlying health problem.

What does your vet think?

Probably not... other than you'd have to look at them all the time and already its an issue.