Hi Shackleton,
The 9.5 sec wake up time is correct for the AD7626. As mentioned on the datasheet, this is the wake up time for when AD7626 uses the internal reference and internal reference buffer to charge up the external decoupling caps( 10uF) on the REF and REFIN pins. The external caps must be fully charged to the correct reference value to produce accurate result.
The AD7626 powers up quickly. When using the external reference on the REF pin, it takes 65us to power up, this assumes that the external reference has charged the decoupling capacitor.
Regards,
Jonathan