Sorry I haven't been on here much of late, not that I am any kind of expert. Glad to hear you got it done, I don't think you will regret it.
You should be able to get your Gearbox code from your data sticker in the service book or boot of the car. Also there is an issue related to flushing the box when they change the oil, I should maybe have said this earlier. 9 litres includes enough oil for the gearbox but that doesn't drain the torque converter, it doesn't gravity drain when you take the drain plug out so there is specialist equipment to put pressure through the system to push out the oil in the TC and re-fill with new oil and this is the correct way to do it but not all garages do this,usually Audi or ZF specialists will be the ones who can. It's not the end of the world if only the geabox gets drained and some people have mixed feelings about the pressure through the system thing and seem to think at times it causes issues in it's self.
If only the gearbox gets done it's only about 7 litres, which mens there will still be about 2 litres of dirty oil in there which will mix wih the new oil on start up, it's not ideal but not a disaster either unless you previoulsy had metal filings or something in you oil i.e. a damaged box. For me to do it myself I wouldn't have the specialist equipment, so I would just be changing the oil in the gearbox sump and I think I am happy enough with this, as the job will get done for the cost of the parts only and I will just make sure it gets regular changes from there on.
Anyway, that's all I would have said if I had been here, I am sure you are not too bothered now with your nice clean gearbox oil already in place, have to say I am a bit jealous, Grrr, nah just kidding, I am genuinely pleased for you, I will get round to mine relatively soon, all the best