What does 9.2R mean in the context of RAM memories

Speed

The numbers are in MHz, and represent the frequency of the clock signal at which the RAM operates (x2 for DDR RAM, so DDR2-800 is running at 400MHz). The DDR means "Double Data Rate" which means it transfers data on both the rising AND falling edges of the signal (instead of just signal on vs. off). So, for example, DDR gives you the effect of 800MHz while actually still only being at 400MHz. DDR2 and DDR3 are superseding versions of the DDR spec. (ie: DDR3 is "double data rate type three").

Timing

Memory timings (or RAM timings) refer collectively to a set of four numerical parameters called CL, tRCD, tRP, and tRAS, commonly represented as a series of four numbers separated with dashes, in that respective order (e.g. 5-5-5-15). However, it is not unusual for tRAS to be omitted, or for a fifth value, the Command rate, to be added on (from Wikipedia).

CL (CAS Latency)

The CAS latency is the delay, in clock cycles, between sending a READ command and the moment the first piece of data is available on the outputs.

LRCD

Row Address to Column Address Delay - tRCD is the number of clock cycles taken between the issuing of the active command and the read/write command. In this time the internal row signal settles enough for the charge sensor to amplify it.

tRP

Row Pre-charge Time - tRP is the number of clock cycles taken between the issuing of the pre-charge command and the active command. In this time the sense amps charge and the bank is activated.

tRAS

Row Active Time - tRAS is the number of clock cycles taken between a bank active command and issuing the pre-charge command.

See here for more info on these and other RAM timing elements.

Voltage

The listed voltage is the minimum/recommended voltage required to power the RAM module. Not enough and it can't power the module, too much and you can damage the various chips on the module.

Multi-Channel Kits

These 'kits' are simply multiple single, similar (identical as possible) RAM modules packaged together. The intention (these days) is for them to be used in motherboards that have dual and triple (etc.) RAM channel capabilities. IE: since you need 2 sticks to do dual channel, and that became standard/regular for new systems a while back (before triple channel, quad, etc.), the memory manufactures started marketing their existing 'kits' as 'multi-channel kits'.

Previously the kits were sold mainly to give a bit of a break on price when buying multiple modules (ie: Two 1GB modules in a '2GB kit' is cheaper than buying two individual 1GB modules of the same model).

On older boards way-back-when which only supported 2GB RAM in total this sort of thing referred to what you would expect to see after on-board video hardware and other devices and consumed some.

On a modern board like this (which supports 64GB as the other specs state) this refers to what memory can be allocated to the on-board GPU - so you might put 8GB in there but only see ~6.25 GB available to OS/apps/games as the GPU has claimed the remainder for its work. You usually have some control over what the GPU does claim, and of course if you completely replace its function with an add-on card (which you likely will if building a machine for gaming) it should take 0.

This information is normally listed with or directly after the name/model of GPU in a specs sheet, I assume that line has been missed out by mistake in this case (either a mistake on the seller's part or due to them copying a bad list from the manufacturer's blurb) leading to a little confusion.