Yes I have used them, and yes they work.
DD was born with deforemed ears (curved like little shells) - ear buddies staigtened them so now they just stick out.
I put them on at four weeks and left thme on for 2 months. I should probably left them on longer, but was in a totallys tress aobut everything at them time, so jsut took them off.
Yes they are tricky to apply...I had to keep re appying them, but got quite good at it. I always did it when dd was asleep. The company sent me more sticky strips when I requested them, Your are not supposed to take them out at all, but I had to to as the tape came off.
DD was left with a slight blad patch where the tape had been, but it re-grew quickly, and was a small price to pay for her having straight (if sticky out) ears. I didn't realise how well they had worked untill I saw before and after photos.
They work best if applied at birth, so if your baby is already 9 weeks old, you will probably have to leave them in for 6 months, I would imagine.
I have posted about ear buddies before on MN, so it might be worth searching the archives.
Remember thogh, that she might "grow" into her ears. DH still thinks he has sticky out eares, as his did seem to stick out as a child, but they honestly don't now.