Your taking your fantasy and chinese propaganda for reality....land test hitting a moving target was done sometime ago, i read some article about it. i think it was concrete block moving or something.
china NEVER announce Jxx, it was just rumor from internet. there whole bunch rumors about china military most are false. if you create 1000 rumor, eventually one will become true. goto sino military website, there are also rumor on new SSBN, new stealth, etc etc.
the DF21D was confirm by both chinese and US government. is it at deployment stage, no. does it chinese work on it, and US military belief its workable, yes. Its not something revolutinary like railgun/laser weapon etc. all the component to make it work are there, test it. its diffcult but not impossible.
all modern ballistic missile etc can have mid course correction, it has been done before. an active seeker MMW on DF21D, mach10 can be done, its not the 1st time seeker been put on hypersonic missiles.
the only diffculty is terminal guidance/accuracy and detect/ID/track CVBG in real time. only the former case are related to DF21D, the latter is combination of UAV, OH radar, Satelite, diesel sub etc etc.
my guess is china still has diffculties to make the DF21D accurate enough to hit a moving target. the accuracy has to be within few meters.
so the fact is US military said DF21D is in IOC, chinese general said the prototype is deployed and start testing etc. and yet you argue its impossible. do you know something that US/Chinese don't? of course there is a chance where china couldn't solve the issues or other reason and cancel the project. but i would not say its ridiculous they can't accomplish this task