how critical is the 9000m valve check?

i ask because due to an impending divorce battle i,m skint and im at 8300miles i wanted to use the bike more this summer if we ever get one up here and im worried that i,ll maybe damage it by over running the service by say a couple of thousand miles, i,ve changed the oil but i,ve never done valves before so i,m not confident enough to try it,i,m pretty sure its about £400 or thereabouts to get it done and i just cant stretch to that right now, any advice appreciatted

You can get cheap shim kits from the US and the gasket kit is not expensive also. (Harley ones have better choice)
As suggested above, do it yourself.
The main thing is to do a proper measurement and write things down in a neat order so you know what valve has which clearance.
Get the shims out and measure them or read what size they are.
Then either use a spreadsheet or a bit of math and paper to determine what shims need replacing and the size they need to be. It is just adding or subtracting.
Fit it all as per manual and check measure, and check again....
But the covers back on and all is fine.
A good practise is to take disconnect something like the plugs to the coils and give it a crank to see if all is smooth. If all fine reconnect and start it.
Also get a mate or a forum member who done it before or who is a mechanic to look over your shoulder to do it the first time.
Things you need besides the usual spanners:
Metric feeler gauges, 10 mm shim kit or get the needed shims from a friendly dealer. Rocker covers gasket kit, some long nose pliers, magnet, good verniers (pref electronic) or micrometer.

You can take a punt and leave it, open it up and measure if it needs done or bite the bullet and do it properly yourself. As mentioned above normally they don't need much adjusting, but hey you never know.

In the end, it's still just a bunch of bolts and parts so there's nothing scary about it.
Read the manual properly and decide to just go for it. Most important thing might be to take your time and follow the steps.
After measuring the clearance and these are out of spec you can always bring the bike to a dealer or let a friend help you on it.
If everything is within spec you saved yourself a bunch of money

I have to do my shims as well. Just had a look on flea bay at the Harley shim kits Jeheezus theres a fuggin truck load of them.

Which are the right ones.

Niether of my bikes needed anything doing. So I reckon you are safe to leave it. However, I got my SDR serviced and checked at an independent mechanic who charges 40 quid per hour and the bill was little more than 200 quid. Quite a big reduction from the SD I had serviced at Bracken at 400 quid plus and far cheaper than some of the valve check service prices on here of 600 quid

If you are out of warranty look for a cheaper, but competent, mechanic to do the work or ignore it until the next service.

Here's the maintainance schedule and what they're supposed to do for your money:

I stripped mine down myself, I was confident in my ability to check them but not changed shims before so if it came to it I was going to send it stripped down to the workshop to get them to complete it. Why pay quids for an apprentice to get it to that point. BTW at 30k km they were still fine.

Dealer recently did the 9k service on mine (I did not do the earlier one) and 3 valves were OUT of spec. It is a dealer who I have used for a while, as has my buddy, and think they are not bs'ing me.

All ways a flip side to think about. Splitting the sheets is hard on all and fooks with your head. It might not be the best time for you to open up your motor. More like time to ride it...with caution..cause you head might not be screwed on right at this time of your predickunment. A few K miles? Just go easy and don't wind the crap out of it. Bets are off if it's your track bike.