What is the best way to get to enoshima?

Hi,i will reach narita airport ard 7.30am, after getting metro pass and bmobile ,i planning to take nex to ofuna ,however if i take the 9am + train,will only reach about 11+, i "ll be staying at ikebukuro, is it if i take from ikebukuro to kamakura,it will only take 30mins travel time? How do i get back from ofuna to ikebukuro? For metro pass i just get it from ticket box right? As i check travel centre open at 9am while ticket box open at 6am

if I take from Ikebukuro to Kamakura, it will only take 30mins travel time?

No, it is not so fast.
It requires 1 hour and a little 5 to get from Ikebukuro to Kamakura by JR, taking either one train bound for Zushi or two trains with a simple transfer at the same platform in Totsuka.

Getting to Kamakura Station by JR, you can pass through a transfer gate to Enoden with a valid ticket, pass or IC transportation card.

- japan-guide.com: Enoshima # How to get there
http://www.japan-guide.com/e/e3117.html#jump_access

How do I get back from Ofuna to Ikebukuro?

I presume you hope to know a route back from Kamakura to Ikebukuro.
You can either take one train bound for Utsunomiya / Koganei from Kamakura to Ikebukuro or take one train departing at Track 2 from Kamakura to Totsuka then take a Shonan-Shinjuku Line departing at Track 1 to Ikebukuro. (Please feel free to ask a JR station attendant in Totsuka which train you should take.)

getting metro pass

Why do you plan to get a Tokyo subway pass on Day 1? How would you use it?
(Kamakura is a city in Kanagawa Prefecture, where no station on Tokyo Subway Network is located.)

Whether a transportation pass pays off or not depends on destinations and traveling paces.
Some tourist spots in Tokyo are better accessed by JR from Ikebukuro than by subway.

JR companies are not operating any subway line.
Tokyo Subway Network is sustained by two operators.
A Tokyo Metro Open Ticket can be used on lines of Tokyo Metro subway only.
A foreign visitor flying in to NRT / HND can choose a Tokyo Subway Ticket, which can be used on both Toei and Tokyo Metro subway lines.

Let me delete "5" after "a little" in my previous message.

To get to Enoshima first then to Kamakura second, you can take a Shonan Monorail train from Ofuna Station to Shonan-Enoshima Station, then use Enoden from Enoshima Station to Hase Station and walk to Hasedara Temple or Kotokuin Temple, where Great Buddha of Kamakura is.
- japan-guide.com: Kamakura: Access, Orientation and Transportation
http://www.japan-guide.com/e/e3115.html