Not possible, whatsapp was created for 1-on-1 communication to prevent spying and more.
The whatsapp server would know when the same number is used on more than one device... it will only communicate with the lastest registered device.
Meaning the first device would get blocked out, it doesn't matter if they don't run at the same time. It simply wouldn't work.
My advice just use a prepaid number or your home phone... a robot will call your home phone there's no need for a SMS capable telephone
a robot has not called my phone for several hours after waiting i had to change the number yet still it did not call with verification code, how do i solve this?