夏威夷:is 8-9 days enough for 2 islands:Maui and big island

When is the good season to go there? early May or early June, which time is better?

how many days is enough for each island?

What are the must-sees in each island?

How to plan the trip? I am in the bay area, CA, should fly from here to which island first?

How to connect the flights between the islands? (I've been to Oahu).

What hotels will you recommend on each island?

Any tips?

Thanks for your advice!