The default behavior of this extra button is that a single press will interrupt whatever you’re doing on open Samsung’s in-house assistant app. With the Bixby app update, a new option allows you to set the Bixby button to require a double-press to open the Bixby app. This is unlike the Galaxy S9+, which lets you disable the button from doing anything when pressing it. In either device, pressing and holding the Bixby button will still initiate a voice command.
When the Samsung Galaxy Note9 launched, many were upset that the Bixby button, could not be disabled to prevent accidental presses as you could on the Galaxy S9+. Many people, myself included, might accidentally press the Bixby button at the most infuriating moments such as when rushing to fire up the camera before a picturesque moment is missed.
Anyway, the problem is somewhat fixed. Samsung still wants you to somehow accidentally use its smart assistant. The setting can be found by opening the Bixby app (press the Bixby key), and head to the Settings in the three-dot menu. If you don’t see the Bixby key option among the settings, you’ll have to update the app by going into Galaxy Apps and manually updating Bixby.
I want an option when I click Bixby button that should tell the time even when locked
They don't charge any extra.
"This is unlike the Galaxy S9+, which lets you disable the button from doing anything when pressing it". So, they shove an unwanted feature down the user's throat then charge extra for disabling it. Great customer care, Samsung!