Where have you got your number ""80-90%" from? If he's calling with Qhigh and better thats like 17% of hands. Meaning to be folding 90% of the time, he'd have to be opening 170% of starting hands.
Have to admit I genuinely don't understand this. If he's calling 17% that just means he's folding 83% to me and my guess on %ages is about right.
That implies his opening any two cards though.
He's probably only opening at best 50%, and of those hands, if he's calling with say 55+,A8s+,KTs+,QTs+,A9o+,KTo+,QJo (you seemed to infer he'd call pretty wide) then that's 16% of the total hands dealt therefore about 1/3 of the hands he's opening (16/50 ~= 1/3)
So he's folding 66% and calling 34%. K4o has 31% equity when called by those hands.
So 66% you win 1800+300+600+(50*9) (assuming antes 50) = +3150
Of the 34% you get called 10% you double up, 10000+300+(50*9) = +10750
and 24% you bust = -10000
So the EV of the shove is (0.66*3150)+(0.10*10750)+(0.24*-10000)
=+754
So it's +EV by just over 1 bb.
This is with our very leniant assumption that he's opening 50% of hands which includes hands such as J4s, Q2s, K5o, J7o which most people don't open from the cutoff.
So to conclude, it's very slightly +EV if you think he's opening REALLY wide, but in reality he probably isn't and it's probably a slightly losing play which is really unnecessary in this sort of comp.