Better actuator and elc boost controller will bring on boost as quickly as it can.
No point in runnin 9psi on a bigger turbo... Find a HKS 1 bar actuator (or generic and make it fit) and just use that, will work well with the bigger turbo, also check to make sure 12 to 1 AFRs are ok on that boost level and its not pinging! Most ppl tune to around 11.5ish to 1 that ive seen on the rb25's.