Singapore is great-- but--
you should be aware that as the gap between what school offers and what your child needs GROWS (and it will-- it's just a matter of how rapidly), you'll be hunting harder and harder for a different school placement as the fit gets worse.
Many parents who don't have another good option wind up homeschooling, or doing something similar to it.
Honestly, I understand if you aren't ready (or able) to take that step, but if you're not, I'd be careful how much on-curriculum or even on-topic afterschooling/enrichment you do.
Personally, we've found it better to NOT afterschool/enrich things where my DD has to endure lower level instruction IN the classroom. Because if we do, we make that gap
intolerable for her (as opposed to merely "bad").
Kids who are highly gifted + are a different animal here-- they learn in ways that are kind of jaw-dropping in terms of how LITTLE input they require, and how fast they can go through it.
At your DS' age, DD was plowing through a year of Singapore math in about 10-12 weeks. This is why by the time she was 7, she NEEDED to be doing pre-algebra, which the school absolutely would not consider in spite of her clear readiness. Well, they might have-- if it had only been math. But it wasn't.
Asynchrony is a real problem if you encourage the cognition/maturation gap to widen further. The world at large has a great deal of trouble dealing with kids under 10 who are ready for post-secondary instruction. Just something to be aware of.
I'd foster
other extracurricular interests that he can sink his (considerable) teeth into-- robotics, chess, etc. Maybe branch out to a different instrument, or (since you said he's been taking lessons about 2y) see if you can wait that one out (I guarantee that he will eventually hit a wall where he'll feel like he's not making as much progress as he likes on as little practice as he prefers...
BTDT), or maybe add a second artistic domain to explore.
He's a little young yet, but working with animals has been
amazing for my DD. She can't rush it, she HAS to slow down, and she HAS to put in the time.
