There are 2 prerequisites to achieve this.
1) You will need to have a Pro-level Zoom account to be able to disable the password option.
2) The waiting room option will be enabled automatically when you disable the password, this is a restriction from the Zoom end.
After this, you can disable the meeting passcode option in your Zoom account for your specified meeting host. Consequently, the plugin will not show the password field if the meeting password is not set.