How come has nobody told me about this ???
... Being at first too lazy to read the whole article, (and I will never say that enough: the more it goes the more we tend to take for granted anything we read on the Internet, especially on wikipedia !). Out of curiosity, I finally ended-up looking up the IETF to find out a little bit more about what should certainly be a "highly advanced evolution" of our good old but yet familiar IPv4 protocol. I got this result: IETF RFC1606.

Let's take a closer look at that RFC:
Title: A Historical Perspective On The Usage Of IP Version 9
What ? this is not even barely new, and I'm not even aware it ever existed ???

OK, let us see how old it is:
Issue date: 1 April 1994
OK... now I'm starting to connect the dots... what I am reading is one of IETF's excellent April's fools :) (remember that IPv4 packet evil-bit field ? another one of 'em). Still a good laugh (provided you're a geeky network engineer, which kinda restricts the audience) here, where you can find all of IETF's pranks.

I especially like this one extract:
The introduction of body monitors as IPv9 addresseable units injected into the blood stream has been rated as inconclusive. Whilst being able to have devices lodged in the heart, kidneys, brain, etc., sending out SNMPv9 trap messages at critical events has been a useful monitoring tool for doctors, the use of the blood stream as both a delivery and a communication highway, has been problematic. Again, "L0Lz !!!"

More seriously now, IPv9 also corresponds to other serious stuff (but still funny if you consider it is 3 versions ahead of IPv6, there has to be some meaning behind that).
To make it short, IPv9 is very often referred to as being a chinese technology, more can be learnt from this article.
From what I understood by quickly reading, IPv9 comes from China (and is supposedly the only country where it is deployed) and is supposed to address IPv4 address space deprecation. It also seems to include an hybrid DNS facility, to manage Numerical Domain Names, cross-compatible with IPv4 and IPv6 DNS, to handle numerical DNS ressources instead of Litteral DNS ressources.
Sidenote: Writing that above paragraph, I just came to realize I mentioned "IPv9 also corresponds to other serious stuff" therefore having serious second thoughts about it...

What I aslo read, is that IPv9 could refer to TUBA, as in RFC1347, aka TCP and UDP with Bigger Addresses , which would be yet another ipv4 address space deprecation solver but in an even more funky way: this one deals with using re-implementing TCP and UDP over CLNS/CLNP (Connection-Less Network Service/Protocol). For those who don't remember, CLNS/CLNP is an OSI Layer 3 protocol, just as IP is, that uses NSAP addresses instead of IPv4 addresses. CLNS/CLNP is a part of the IS-IS OSI generic routing protocol suite, which is very often used to route SDH/SONET supervision addresses (of such ADMs for instance), of the NSAP format.

Before this article gets too boring (and I strongly suspect it already is!), this again teaches me once more that same crucial lesson:
Wikipedia, or any other info from the Internet, is provided as-is. It always does require checking, since there is a strong chance it is either unclear, hoaxy, incorrect...or just irrelevant. This pretty much the only point this useless post should make, by the way ;)