CPR address change - Is it necessary?

Dear Members,

Greetings of the day!!

I am currently staying in Juffair on an annual contract. I have got my CPR and driving license issued  on the same address proof in Juffair.
I wish to relocate to Riffa area as I have to commute almost everyday for work there. I found a person who is planning to send his family on exit and wishes to sell off his household items. I enquired about the flat and he said he will vacate it once his family leaves. However, he told me that the EWA is in the name of the bahraini owner and cannot be transferred and hence he cannot give me the address proof.

I would like to know:
1. Is it necessary to update the address information for the CPR and DL?
2. Is it ok to transfer to a flat with EWA in the owner's name? (pls note that the rent is exclusive)

Would be waiting for valuable recommendations.

Thanks in advance