Yup, Air 9’s can be fragile certainly the seat post area of the older versions (v1) that was sorted out by a more beefed up v2 and I’ve not heard of any issues and I have two mates that race Air9’s, one rigid and one bouncy.
I prefer them rigid and SS, I had mine down to17lbs before I sold it to fund my CXer. I had mine kitted out with full RDO and SRAM X0 and it was peachy indeed.
It does depend on what type of riding you intend to do on them ,let’s not make out they’re ace at rocky hacks or the stuff you get in the North Yorks Moors because whilst light and strong, they’re hard work. If on the other hand you’re using it for wooded single track then they’re ideally suited.
IMO
However, it’s your £’s and you should at least view the Air9 as an option and your ti variant too.