*x Main Sasuke
*x Guy *x
*x Asuma *x

Ghost Kill tactics.

3
3
x
3
2 Talents with Tonton.

Mysteries:

T1 : Sasuke and Main
T2 : Guy and Asuma
T3 : After Guy attacks use Sasuke
T4 : Sasuke and Main

That's pretty much best you can do with purely f2p ninjas, but even f2p can get some rares. The upgrades for 9 tails are Wind Blade Asuma, Iruka, Darui, Danzo, Hashirama, Mifune. Unless you got some of these ninjas * with above line up.

Use third attack it's lightning element so it does more damage, 9 tails is weak to all elements. Sasuke is probably better on first row, so you don't get unlucky and loose WB buff on main if fox hits him.

This is the best form for f2p (unless you got lucky Hashirama), Darui is only more dps then Sasuke if you retreat before his field runs out and revive with coupons.