do we need a JRpass?

Hello all,

we are a family, our oldest son counts already like an adult and a child, we plan on january to visit japan, we need a train from Osaka to Kyoto and maybe Kyoto to visit something near (we are not sure yet, if you have some suggestions would be great) and then from Kyoto to Tokyo. Do we need the JPrail pass? It is necessary or can we do something else too?

Thank you