Two more weeks and I've beaten him at age 9.5. If I can keep up this pace, I'll be a grandmaster by April (that's how it works, right?).
I shellacked Magnus (well, 9-year-old Magnus, at least)

age 9 took a while to beat. Age 10, if you can get to an endgame with equal footing (which means not falling for his one out of 300 trap lines he somehow knows) then you'll do fine.
Another fun win against the world champ, age 9, this time against the London System. He didn’t play brilliantly, but I was pleased with the way I developed and maintained a space advantage
Still no luck against age 10, though!
Magnus age 9 is the bane of my existence. I beat him maybe once out of ever 15 games. I can usually outplay him into the late middle game, but almost inevitably I can't come up with a plan and I end up blundering or allowing him to achieve equality. Last night, though, I beat him soundly with Black in the Ruy Lopez, and I had to share.