I have deployed for 7 months.. which ultimately left Titan with someone for a little under 8 due to training and all that. I will say that I didn't get the welcome home from him I had hoped.. not to discourage you at all jsut being honest. He was brought to the airport and showed little to no interest in me. Then when he was finally brought to my house with all his things.. he was way more intrigued.. familiar smells, familiar space, yard, etc. I wonder if his response, was in large part due to that he was uprooted and given to a not super familiar friend, and just adjusted to the new life style, going "ok well this is my new home." Then didn't know what to do when I was back. We fell immediately back into step.. same routine, same exercise, same training, all that. He didn't skip a beat. We ran into stuff a few months later, but I don't think that had anything to do with the seperation.
That being said I go a year or more without seeing my parent's dogs that were there when I lived there 7 years ago. They still remember me and come charging up when I get there. And I know they remember me because Cocoa, the chocolate lab, is scared of life itself and she runs right up to me for belly rubs and our old routine.
So I think it is dependent on your dog and your situation. Are you able to visit with him at all or is this completely impossible? In the end.. I think you guys will be fine.. even if the worst happens, where he doesn't appear to remember you, he will integrate right back into your life style, promise