Niky - I'm sorry to hear that you're going through this with your lo! I totally understand - ds also had reflux and was sleeping in his car seat for the first 9 months! I then realized that he had to get out of the seat, so I had to use pu/pd to help him learn to sleep in a crib.
Actually, with a baby at 9 mo, I think the pu part is too distracting - I only did pd (I basically stood there with him and almost held him down with my hand - no patting, no shooshing - again, too distracting for the older baby). It took a long time (I was sometimes in his room with my hand on him for 45 minutes, waiting for him to begin to drift off), and you don't want your hand to become a prop either, though. Just make sure that you begin to remove your hand as he starts to get sleepy. Then when he fusses, put your hand back on him, remove it when he drifts off, put it back on when he fusses, etc. The point is to calm him without picking him up at this point - when I was going through this, it was explained to me that I should use my voice as well (saying "it's alright, sleepy time") and eventually you will only need your voice to soothe him, but that didnt' really seem to work for me.
Also make sure that he has some fun play time in his crib (or cot!) during the day. This will help him to feel comfortable there during nap time as well.
If you're really concerned about him sleeping lying down due to the reflux, you might want to consider a "reflux wedge", which is like a little sling that they sleep in in the crib. We had one - once again, didn't work for ds, but you might want to give it a try if your lo is too uncomfortable to sleep lying down. The one we used was called a "Tucker Sling" - I can get info on it if you're interested. I would even mail you ours to try if your lo wasn't already 9 mo (the weight limit for the one we have is 16 lbs). I found that there was no way to elevate the mattress, even only slightly, without my ds rolling down and being upside down!
I will try to find the thread that I posted on during my "battle" as I like to call it - it might help a bit.
Hope this helps you a bit - hang in there!!!!!!
Maggie