Hello A-roaming. Here’s our experience, for what it’s worth.
Our daughter is in second grade at a local school. She’s a “joint venture” (Chinese-Caucasion) and doesn’t experience any bullying but she’s pretty sociable. In fact I think she sometimes gets away with a little more and is made a bit of a fuss of because she is “foreign” (I think the only one in the school.) I’m not sure how much Shanghainese is spoken but I think it’s discouraged. Certainly our daughter has never shown any desire to speak any Shanghainese.
As for the schooling itself, it is tough. The school day is from 7.50 to 3.30 and she gets about 2 hours of homework each day (at least, it takes her 2 hours). The schoolday is actually 40 minutes shorter than last year as I believe the government mandated a shorter day to reduce the pressure on children. Mom spends a lot of time every day helping our daughter with her Chinese homework and you’ll definitely need someone who can help your children with this. She was fluent in Mandarin before she started school and could read a fair amount of Chinese, although not write any, but the local kids seem to have been preparing for school from about the age of 4, so I think she was actually a little behind at least as far as writing goes. I think your 9 year old especially would struggle unless he/she is reading and writing Chinese at close to the local standard. I also wouldn’t expect any help from the school in catching up. The style of teaching is very rigid and doesn’t seem to cater for individual needs. The maths standard also seems to be fairly high – at least a lot tougher than when I was at school. Having said this, the school she is at is supposed to be a bit tougher than average but I don’t think other good local schools would be that much easier.
I don’t actually regret the fact that she is at a local school but it’s been heavy going at times and sometimes do wonder. My feeling is that she is getting a very good basic education and hopefully the ability to read and write Chinese will be something that sticks with her.
Hope this helps a little.