I have done several zetec turbos with std pistons, broke one set too (ringland) then upgraded to wossner forged.
thw way i see it is you have two options (in my opinion) go with what you have and a single normal gasket (despite what you think 9.5 is not that high, my friend is currently running 14 psi in a v6 24valve golf at 10.8:1 compression ratio) the secret is all in the "tune".
The other option is to use an ALU decomp plate, but this will only move your torque curve and not allow you to run more/less boost as the pistons are still not any stronger. Decomp plates are very good if used correctly.