Telemetry

Not being able to afford a new Taranis setup I thought I might upgrade my Futaba 9 to something that will give me some telemetry. Height, speed, battery voltage, variometer. I went to Banggood to find a bewildering array of stuff, what the hell do you need? Can anyone help?

I'm not familiar with the Fut 9 - does it speak to you? Taranis does. If you have to take your eyes off the model to look at a screen, telemetry modules aren't much use, because by the time you look back and focus, the model will be somewhere else!
Variometer - tells you if the model is going up or down.
Altimeter - usually combined with the vario (it is with the Taranis) tells you the height above ground (no kidding!)
Battery voltage - there are two kinds, one for lipos, that plugs into the balance lead, and can be configured to tell you lowest cell voltage, or pack voltage. Saves you watching the timer to see how much flight you have left! They also tell you when the pack/cell voltage is low, and it's time to land - quick!
The other kind is for the 4/5 cell pack used in i/c models.
Speed - gimmick that serves no real purpose. Can be used as a pre-stall warning.
Temperature - can be used as an egt, cyl head temp, or lipo battery pack temp.
Fuel level - same as the gauge in your car - for i/c models.

For gliders you want vario/altimeter, and lipo battery volts.
For i/c - none of them, really! Fuel level is ok if you are just pottering about in gentle circles, but if you are aerobatting -

With Taranis, you can set the modules to report when you set a switch, or you can set them to repeat according to a timer you choose, from every 5 seconds, which can be very annoying, to once a minute, which can be too long! I prefer vario constant, battery lowest cell report every 30 secs, and alti on demand.

None of my TXs' talk to me! The Futaba 9CP was a 35meg set that I upgraded with a new plug in module to 2.4gig (Assan). I was hoping there'd be some kind of after market upgrade. After all most of the FlySky RXs' say Telemetry on them. I am quite prepared to buy another module (FlySky obviously) but what do you also need? Surely someone must be doing after market upgrade kits.

Sorry, Tony, can't really help, then.
Have a browse on here, you might find what you are looking for.
www.banggood.com/Wholesale-Radios-and-Receiver-c-4587.html

That's where I was looking, I always thought I was 'Tech Savvy' it seems not!