I haven't read the other replies so sorry if I'm repeating what others have said...

Huge hugs. It's so tough when they just won't settle! The two things I thought were

A. at 9 weeks, my DD2 was only up for 45 minutes then back to sleep so your DD may very well be overtired. And if she's stimulated, you may be missing the cues or she may be hiding them as she's too interested in whatever else is happening. I'd try 45 minutes of awake time then back to bed.

B. reflux. It's often at its worst 90 minutes after a feed so your DD could very well be in pain from the acid rising. My DD1 had silent reflux and rarely slept during the day until 6ish months unless she was in the sling. Even the pram didn't cut it for her! DD2 has reflux also (but it's not silent, she is a spewer) and the acid attacks are awful but she does settle well for sleeps however I have to be onto her or she very quickly gets overtired and extremely hard to settle. It's only been the past maybe 4 weeks (possibly less) that she's gone to 1.5hrs of awake time between naps.

HTH a little. Hugs again.