Low octane pump gas

since low octane pump fuel is very unstable and can easily cause knock........if a cooling agent is used , such as Water-Meth Injection, would this reduce the chances of knock under load? Given that boost is at 0.7 bars or 10psi

Yes a water/meth injection help, in some engines help alot (EJ with topmount intercooler is in top of my mind).

What engine are you running? and what octane (ron)?

Yes, water methanol injection can be used with great effect on an engine that is turbocharged and running on pump gas.