The act of taking the loan out of deferment will not improve your credit score (just as putting a loan into deferment does not, in itself, hurt your score). As you pay down the loan, however, you will begin to see improvement.
If you were able to pay it down to a certain point fairly quickly, you could see a boost in your score. If you were able to bring the principle owed down from 100% of the original loan amount to below 80%, for instance, that should benefit your scores (how much depends on a lot of other things, like if there's anything else holding down your scores). You can, by the way, make payments on your student loans while they are still in deferment. So if you had a chunk of cash you wanted to apply to them, but you weren't ready to start making regular payments, you could do that.
There's something else to consider, too. Are you looking to raise your score because you plan to apply of some other kind of loan soon (like a mortgage)? Is so, be very careful with this. Taking your student loan out of deferment early will add that payment to your debt to income (DTI) ratio. That may make it harder to qualify for another loan. If it's coming out of deferment soon anyway, it might not make a difference, but you should definitely talk to your loan officer about it before you make a move like this.
