The data fits a Gompertz curve with this formula fairly well:
=ka*EXP(-EXP(kb-kc*xdata))+kd
where
ka -9.21E+00
kb 2.17E+00
kc 9.25E-02
kd 9.11E+00
The sum of the squared absolute error = .764
which is not good enough for the precision required.
If we consider only the 7 data points around 11 and
apply a second order polynomial, the results might be good enough:
=TREND(ydata,xdata^{1,2},11.3^{1,2})
=8.78598