well that is the passive part , just being able to be normal in public ---- the "working" service part requires a great deal more , and training, and proofing .
I'm glad things went well, but at that age he isn't a service dog, and isn't yet a service dog in training. He would be considered a service dog candidate. I'm not familiar with the specific laws for your area, here service dog candidates don't go into public where pet dogs are not allowed.
We are going to be training our dog to be an autism service dog as well, although we are in the US. Our trainer told us that once the dog has completed a good portion of training, we can call the stores and ask if our service dog in training is allowed in. Right now our dog is only 12 weeks and hasn't even started a training program, so like Lin said, he is just a candidate at this point.
I would be extremely hesitant to bring such a young puppy into a store around children without any formal training. I don't even mean service dog training - just training in general. The dog is still new to everyone and doesn't have a very firm grip on how he should act in certain situations. We practice by taking our dog to the pet stores here and to public parks, but I wouldn't take him to a store (especially a toy store) until he has completed a good bit of training.
Bringing a service dog in public also represents other service dogs, so just remember that when bringing a pup out in public. He doesn't have the skills and training necessary to perform any type of job at this point and probably doesn't have the training to know how to react to certain outside situations. I'm happy so far its gone well, but I would just be cautious at this point. There are some great youtube videos about service dog etiquette that might show you how a dog should act before it can go in public.
I wish you all the best and I hope your training goes well!