Nice to hear from you again.
It's unfortunate that the school chose to re-test only 12 months later on the WPPSI, as that is well shy of the best practice 24 months between administrations. Fortunately, he doesn't appear to have huge practice effects in his scores, as they are very consistent with last year's testing. Nearly identical, actually, and well within the standard error ranges.
I will reiterate that none of his scores are low. His visual spatial and working memory skills are comfortably average, and are only lower than his verbal and abstract reasoning strengths in comparison. The relative weakness in VSI has potential to affect his performance in traditionally academic programs mainly if it turns out that handwriting becomes an obstacle to meeting output demands (and possibly in geometry--but with his strong fluid reasoning, that's less likely). There are cases where it affects written expression, because of impacts on writing mechanics and fluency, but it's far too early to be making that call.
At preK/K age, a fair number of essentially neurotypical children have yet to establish clear handedness. Most OTs I have worked with recommend that ambidextrous individuals pick a hand (probably right, for general convenience), and just work on developing it for writing, as your OT appears to have done. He won't need handwriting at the same level as his verbal cognition to demonstrate skills at that level. Just average handwriting will do. In the meantime, while his handwriting develops, you can scribe his stories, or audiorecord them, if he has interesting thoughts to express that his hands can't yet keep up with.
And with regard to schooling decisions: despite what you may hear from the community around you, there is no need to feel that a placement decision made now locks him into his entire future educational and career trajectory. His needs and your family's needs will change from year to year. Give yourself some freedom to adapt.
