I'm not happy about this.
I don't particularly doubt that it was accidental ingestion, and I'm prepared to accept that the dose he took wouldn't have given him an advantage, so I'm OK about some reduction from the 24 month standard, but four months is pathetic. To be honest, I thought 9 months was a bit light.
The best possible scenario is he was careless and he should have known better. There is an advice line they can call to double-check things, and he's not some newbie who was overwhelmed by life on the tour.
It's just not a good example to set, that claiming you "didn't realise" is the kind of excuse that allows a very substantial reduction in the ban. It's just been like an injury break for him, except he hasn't had to deal with an injury.
I don't think this decision should have much impact on the Troicki case, as this decision seems to be based on a judgement of how careless he was. With Troicki, it's a straight case of him refusing to follow the rules. There was no carelessness involved. He has to rely on claiming he didn't realise he was obliged to take the test, and that's much harder to get out of. He was there, on site, surrounded by people who could tell him that he had to take the test, and who probably did.