An electrical device like this requires a reverse leakage current of 500nA @ 6V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 9.1V.For operation, diode reaches 900mV @ 10mA at the maximum voltage - Forward (Vf).
BZT52-B9V1J Features
reverse leakage current of 500nA @ 6V 500nA @ 6V is the maximum voltage (Tol)
BZT52-B9V1J Applications
There are a lot of Nexperia USA Inc. BZT52-B9V1J applications of zener single diodes.