Out of curiosity what dx11 features were you needing which dx9 doesn't have?
or are you just going by the fact that 11 is newer so must be much better?
Im just a little worried that you're determined everything must be perfect. Great games don't have to be perfect in every way, in fact working within some tight constraints can be very productive.
Well, yeah, the thought occurred to me as well, but I really didn't want to handle all the issues.
Fact is that D9c is mature, 11 or coming 12 not which means that some things are available in it that are not full featured or stable yet in the latest version in terms of tools or third party libraries available for the latest, so for this reason I feel that it is about an even trade between the two versions of Direct3D (or DirectX). The 9c will be mature, stable, and running in all the OS updates for runtime for years to come with very many stable libraries for it and tons of workflow pipeline tools, many of which are actually open source and no cost.
Working with too many new, shiny options can be restrictive for the reasons that I mentioned. Its kind of like buying a brand new car that doesn't have all the bugs worked from it and also doesn't have the supply chain and tool issues fully provided yet. We really haven't even gone deep into the hardware acceleration problems which will increase in trying to reach more than one chip subset in all the different makes, models, and years of computers.