Need a bicycle recommendation

This is perhaps best in a dedicated thread. Let’s see what the mods do.

I’m enjoying the pictures of your son and his bike. My son is nine years old and is itching to get a better bike. Can I ask when your son started riding a real road bike? I asked about this at a Giant store before and they recommended waiting until the child is 150 cm. My son is 140 cm. I think he’s ready for the switch. I know he would enjoy the mountain by our house much more with a full range of gears, rather than his present 7 with no real gear for the steep parts of the mountain.

Any thoughts?