why isn't he going as well? Can't he leave work?
All I can say to help is that it is possible and so long as your DP is fully behind you going, and can get out to visit you at some point in the 9m, you should be ok.
I am married to an Aussie, now in Australia - but for 4 years, he went back and forth to Australia. The longest we were apart was nearly 8m and it was hard, I kid you not.. but with all the computer communications now, like Skype, Messenger etc. with video links, it's not as bad as it would have been years ago.
Make sure your DP is really happy with your choice - or resentment on his part could lead to him doing something remarkably stupid - but also I hope that he sees it as a great opportunity for you both as well, and lets you go, otherwise the resentment will all be on your side.
I hope it works out for you - 9m is a long time but it's not forever, and lots of people have jobs that take them away for 6m at at time (Oil riggers, navy, army) so lots of people get through it. Perhaps you could try posting on the Forces Sweethearts board as well to see how they cope with the separations?
And seriously consider him coming out halfway through.
Good luck!