So I have learnt the standard charts for 9-man raise-fold preflop with no earlier raisers. How do I adjust for a raiser in a certain position? Surely there should be call-3bet charts but I cannot find any. Any maths on the subject would be most welcome.
The reason you don't see this ... are you really keeping track of every players opening percent, at every position, and then on top of that, keeping track of their 3bet percent in every position against openings of every position? Its doubtful.
In this situation its easier to just apply some basic logic/math.
If someone opens, you assume they are using the proper opening range for that position (unless you have have them marked as having an opening percentage that is too high/too low, to expand/contract that range).
When the 3bet comes, you should assume, in turn, that this person believes they can beat the openers range, which means they probably have a holding in the top 50% of the openers range. Probably a little less due to blinds giving them better equity.
When it comes to your hand, you want to be somewhere around the same range as the 3-better to call - that is your hand is in the range which beats the upper half of the original openers range. Now if you in turn beat 50% of the hands in the 3-betters range, which in turn beat 50% of the hands the opener has) then it would make sense to 4-bet.
This is of course talking about a cash game that is deep stacked.
I once heard a professional, whom I really respect, say "If you are calling raises with more than 10% of your range you are almost certainly a losing player". And through all of my hours playing both live and online, I have to agree with that statement.
So, what does that mean? Folding is rarely a mistake. If you folded to every time someone raised, you could probably still turn a profit in poker.
But of course you want to have some range. So how about just picking top 15 of your hands in your range (not 15% but 15 hands) and playing those. For most people that's going to be AA-22 and AQs+ and that's it and that's OK.
Will you give up some value over the long run with this? Maybe. But you'll rarely be making a mistake and putting yourself in bad positions there. If you want to consider balancing your actions, you could consider 3-betting with the bottom end of your 15 hands. Go ahead and three-bet every other time you have pocket 5s (which, spoiler alert, wont be very often) and play that way to balance out your range.