The 9th SCB is a limited functionality SCB that implements only I2C/SPI slave and is capable of waking up the device from DeepSleep (like on HW address match for I2C).
This SCB (SCB8) connects to Port 6. If you want to use the SCB, then place the component and configure it to be I2C/SPI slave and enable "DeepSleep" (Enable wakeup from DeepSleep" parameter) capability in the component parameters. This will force the SCB placement to the SCB8.
Meenakshi Sundaram R