Shaun,
The 9s as std are gapped at around 0.7mm (28ishthou) and are far too wide for your conversion.

I personally doubt you have any problem other than this, and they need gapping down to around 0.6mm for your 30+psi T4 setup.

Leads may well be fine depending on age/wear/type Id advise a change to the late 92+ style cap and leads personally if anyone is buying leads.....