You made two mistakes.
First, you don't blame your losses on anyone else's play. (The first
time I ever played blackjack in Vegas, I had a 16 with a dealer
showing a 10. Since it was a five-deck game, I hit, like I am
supposed to, and drew a 2; the dealer turned over a 5, and took a 5. I
was the last player before the dealer, and the guy before me, who had
an 18, turned to his SO and says, "Well, I lost because he didn't
stand on 16 like he's supposed to.") It could have just as easily
went the other way.
Second, you DO spilt 9s with a 6 showing - the only times you don't
split 9s is with Ace, 7, or 10 showing. (I'll take my decades of
studying this along with computer analysis over whatever tea leaves
you looked into, thank you very much.)
Here's the split list:
Aces, 8s - always
5s, Tens - never
2s, 3s, 7s - with 2-7 showing
4s - with 5-6 showing
6s - with 3-6 showing
9s - with 2-6 or 8-9 showing
-- Don