Uplink Power Control ?? It is not a B9 feature : it exists since B5, at least, certainly even before !
In GSM, It is mandatory to enable UL PC to obtain good QoS. (EN_MS_PC = enable)
In GPRS, the UL PC should be disabled for best results, but the feature itself exists since B6 (GPRS introduction). There was no enhancement in B9. Some operators have enabled it, with very safe values.