Signia hearing aids won’t pair with Series 9 Apple Watch

Please try this. It worked for my husband's hearing aids. Make sure Bluetooth is on then on your iPhone, open Settings > Accessibility > Hearing Devices. You should be promoted to connect from there. If this does not work, it may be best to do as Rudegar suggests and contact Signia.

did you try while bluetooth was off on the phone to make sure it did not connect to that

to put your signia hearing aids into pairing mode this is required the first time one connect a bluetooth device

this seem to include some directions how you put them inti pairing mode

signia-assistant_pro_how-to_2020-03.pdf (signia-pro.com)