Let's not let this wrong tender thing get blown out of proportion. I was under the impression that the use of the #30/74 tender was only temporary, being that #9's tender is at present time unusable. It was my understanding that the tender would be going back to the #30/74 when that engine is done with its restoration and the #9 would then be mated up with its own refurbished tender.
Having a different tender behind the #9 is not totally "historically inaccurate". It was common practice on any railroad to switch tenders around to different locomotives for various reasons(I.E. if problems developed in an active engine's tender, one was usually borrowed from an engine that was stored on the dead line). For example, the tender that is currently behind the RGS #42 has seen service behind at least two other locos (D&RGW #'s 317 & 318) and who can forget the sight of the RGS #455 with the borrowed tender of the D&RGW #452. Thus borrowing the tender off of the #30/74 would probably be what the C&S would have done in the same circumstance.
A good many of the steam locomotives that exist today do not have their original tenders. I'd be willing to bet that the #9's tender is not the one that it was delivered with from Cooke in 1884. I know for a fact that the #30/74's tender is not original.
My $.02
Don F.