I have a FF seat for my son, but I decided on a Kiddy one because I don't drive myself and it has to fit in multiple cars, sometimes at short notice, which I know is impossible with some of the RF seats, almost all of them take longer to install than a normal FF seat (and the Kiddy takes less time to install than one of these) and TBH, I didn't have the money to buy one anyway. The kiddy wins hands down for convenience as a non-driver, and it has quite a few other benefits too such as being less likely to be wriggled part-out of, as many children work out how to take their arms out of a 5-point harness. I've seen some threads though which imply if you have a determined escape artist, some children do manage to wriggle out entirely. But it seems to have less of the more-common but low-level arm escaping problem.
I can see that RF is much safer, and it does make intuitive sense to me, however, if I was to choose a RF seat I would make sure to pick one with decent side impact protection as a lot of them look inadequate to my eyes, although this might be because they tend to be pictured with older children in, and other FF seats always seem to have pictures of tiny 9 month olds nestled deep in the SI protection wings - not so much of 3/4 year olds pushing the boundaries of the seat's capacity.
The compromise I made was that I kept DS in his infant carrier until he physically couldn't fit into it any more. When you say "Pretty much" grown out of - where is her head? If the top of her head hasn't reached the edge of the seat yet, then you have a way to go. Or of course if she is approaching the weight limit, but this is unlikely at 9 months. I remember thinking "Oh no! DS is going to grow out of this soon!" and then he didn't actually grow in height/length at anything like the speed I was imagining. I think I just noticed he was near the edge and panicked, but really they grow a lot slower than you expect. There is a big drop in weight gain speed at around a year as well, before then they can gain a kg every few months, whereas after a year it's more like one every year or so. DS is small in weight, but average height, and he fitted into his (mothercare/old-style cabriofix unbranded clone) until 18 months with no problems. If you got a seat like the Britax First Class, she could be rear facing until she turns 13kg regardless of height, and then the seat turns forward facing. If you look in your red book at the centile line she is on you can estimate when this will be. In DS' case I would have been more than happy with it as he hit 13kg at about 2.5. XP kept the First Class when we split though and turned him at 13 months when he didn't need to 
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Personally I wouldn't want to put a child forward facing unless it was the only option before 15 months or so. I probably wouldn't buy an extended rearfacing seat unless they happened to become more mainstream because of the extra cost, the small amount of driving we do, and the other practical issues. And, TBH, when I was making the decision I was already feeling like enough of a freak for breastfeeding to 18 months, using slings, doing BLW, not using time out for a one year old, and I just Could Not Take having to explain myself and my decision on another thing, one which others were likely to witness, comment on and ask about. I know that's a really rubbish reason, considering the main reasons for are about safety, but it was a very real feeling of exhaustion at the time and it was one of the smaller factors which tipped me.
I don't get the arguments though that DCs would hate it. This seems to be adults assuming adult values onto children, IMO anyway. I remember loving and fighting over the sideways-facing seats in the boot of my Dad's landrover when we were kids. And anyway, most children just take at face value whichever way they are travelling, it's not something which they really think about. DS swapped between his infant carrier, which was low down and so more annoying, and FF in his dad's car regularly at age 13-18 months and didn't care either way. (Exceptions made for those whose DCs genuinely do hate rear facing or get car sick.)