Lol. Like chess itself, still timeless.
Estimate my rating based on 'play magnus' app
There are worse things that could happen. The Magnus app is still out there, so still a relevant thread. I notice Chess.com sends me notices on anything I ever followed or commented on. Unless you unlock the Follow button.

I have to say.... you guys are all liars.
1. Magnus at age 9 (no months involved, just the highest level 9) is easily 1800-2000
2. I've seen grandmasters and Magnus himself lose to age ten. Age ten is definitely above 2100 its extremely difficult. I've only beaten it like 5 or 6 times out of 200 games.
3. Trust me, I'm not a slouch I've beaten a player rated 2343. My rating on chess. Com sucks, I prefer lichess.
Magnus age 10 vs. Stabin (age 64) - be kind
1. d4 d5 2. c4 Nf6 3. Nf3 e6 4. g3 Be7
5. Bg2 O-O 6. O-O Nc6 7. b3 Nb4 .
8. Bf4 Ne4 9. a3 Nc6 10. Be3 Bf6 11. Qd3 Nc5. 12. Qd1 Ne4 13. Qd3 Nc5 14. Qd1 Ne4
1/2-1/2.
I clearly had a better position here but couldn't see the win clearly, so took my draw on repeat of moves before I could screw it up.

I can beat level 11 in a long endgame struggle. But I don't have enough opening knowledge for level 12
Personally I would estimate that Play Magnus at age 9 is about 1500 USCF strength. I would say 16-1700 except it is terrible at endgames. I myself am pretty bad at endgames for a 1600 USCF and can probably beat it 9/10 times from a drawn rook ending. Also when it drops a pawn in the ending it pretty much proceeds to self-destruct. I think the major difference between 9 and 10 is that is when Magnus really began to study endgames. As many of you know he is now the best endgame player in the world.
I haven’t played age 8 in a while but I think it is probably about 1000-1200 at most. Although it did beat me once when I was 1500 due to a trap.

There a good difference b/w age 9 and 10, I can beat 9 most of the time, but for age 10, I usually win 3 matches out of 10
Well 1 game doesn't mean much since the 9 year old Magnus makes quite a few mistakes. If you can consistently (5-10 wins in a row) beat him with no takebacks, you'd be around 14-1500.
Magnus Carlsen at 9 years flat was rating 904, so I'd say the Play Magnus app at 9-10 years is around 1200 given his fast improvements.
woah there Magnus 9-10 on the app isnt 1200. LMAO try him out urself
I just forced a draw as black against age 10 after 14 moves. My best result so far. Also drew against age 9, but on review missed a win. Below that I can win. And I consider myself about a 1400- 1600 at best player. Weak at blitz, but much stronger on slower play. I agree that the app is strong tactically, but at least at these levels can be beaten on positional play. I think level 10 plays between 1800 and 2000 strength. At age 10, the real Carlsen drew 5 and lost 5 games in an IM qualifier. So that seems about right.