9, it's pretty much up to you. There is no company policy or quasi official ruling about bringing family in the first few months. I've seen guys leave their family behind and two months later they are a mental wreck. I've seen guys do the same and it worked out fine.
My gut feeling is that if you have a good relationship with a supportive, capable partner, then bring them on day one. Or at least within the first couple of weeks. They will be smart enough to know that you will be working evenings and weekends, and they will need to do their own thing during the day too. The partner can get out there and explore the accomodation options and leave you to get on with the course. I would not recommend being in the Headland hotel for too long with a wife and three year old when you are trying to do the course. The rooms are small...
In the big scheme of things it is only a conversion course, and as Machiavelli said, nothing is as bad as it seems. You will need to relax sometime. You'll feel much more relaxed in the evenings after dandling the three year old on your knee than drinking with the other trainees and hearing tales of myth and woe.
You may now expect a gig of replies that say leave the family where they are.