Yes. Grappled doesn't limit your ability to use supernatural abilities, assuming that it otherwise fits as described in the Grappled condition.Would a wildshape be able to be used when grappled without making a caster check
Grappled SRD Description said:A grappled creature is restrained by a creature, trap, or effect. Grappled creatures cannot move and take a –4 penalty to Dexterity. A grappled creature takes a –2 penalty on all attack rolls and combat maneuver checks, except those made to grapple or escape a grapple. In addition, grappled creatures can take no action that requires two hands to perform. A grappled character who attempts to cast a spell or use a spell-like ability must make a concentration check (DC 10 + grappler's CMB + spell level), or lose the spell. Grappled creatures cannot make attacks of opportunity.
A grappled creature cannot use Stealth to hide from the creature grappling it, even if a special ability, such as hide in plain sight, would normally allow it to do so. If a grappled creature becomes invisible, through a spell or other ability, it gains a +2 circumstance bonus on its CMD to avoid being grappled, but receives no other benefit.
Yes. Grappled doesn't limit your ability to use supernatural abilities, assuming that it otherwise fits as described in the Grappled condition.
Activating wild shape is a supernatural ability that doesn't require any hands. You can do it while grappled without any problems. Note, though, that you're still grappled in your new shape - it takes an action to break free.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.