JR Pass Purchase

Hello, We (3 of us) will be coming to Tokyo Japan arriving via Haneda airport Nov 20 and leaving Nov 28 via Haneda airport. We will be staying in Tokyo from Nov 20, leaving Tokyo Nov 24, going to Kyoto from Nov 24 leaving Kyoto Nov 27 going back to Tokyo to catch our flight back to US on Nov 28.

I have two questions. Would a 7 JR pass be a good idea to purchase to get around Tokyo and get us to and from Kyoto?

Also, how far in advance can I purchase a JR pass if we do need one?

Any recommendations you have for how we can get around would be greatly appreciated. Thank you in advance!