My eldest was quite like your DS at the same age, although all my DCs have been very right handed almost from the moment they were born. I used to say he was like a goalie, as he would suddenly fall over from standing still! His running was slow and ungainly and this was what worried me mainly: he was a lot slower than all the other children, and I knew that would upset him eventually.
Aged about six I got him referred to a motor skills clinic. When we went to the GP to ask about referral I wrote a letter to the GP and sent it in advance, I also took a copy with us for him to read in case he hadn't read it (he hadn't!); this was because I wanted to say about DS getting upset about not being able to keep up with the other children but didn't want DS to hear me saying it.
At the motor skills clinic he was assessed as having mild hypermobility particularly affecting the wrists, hips and ankles. It's not dyspraxia, nothing like and there is not a lot they can do.
DS is 10 now and luckily his writing has always been OK, but still hasn't a hope of tying shoelaces, he can't put the pressure on to make a good enough knot. I have just bought DS2 (3) some wellies, with reluctance, because DS1 couldn't walk in them properly and kept tripping up. And as for the time I bought DS1 Flip Flops - you have never seen anything like it!! - it was as if I had played some sort of trick on him. I didn't know whether to laugh or cry.
It makes me sad when at school they do still make comments about DS1 struggling with arts and crafts projects, or that his writing is a bit too big. Considering how weak his hands are his writing is bloody marvellous. I say: "Yes well he has got a motor skills problem, the notes on this are in his file" < Paddington Hard Stare > but as it's not a serious problem there's nothing much the school can do . . . he is just going to have to learn that he isn't going to be "good with his hands."
In conclusion (sorry have rambled on) I would suggest you concentrate on his writing and possibly ask for a referral in a few years' time.