No, Seeking Spell does not work with fireball.
Seeking Spell states:
A seeking spell’s range can bend around obstacles to reach the intended target. You can define the route yourself or unambiguously identify a target and allow the spell to determine its own path. However, the spell fails if it would have to travel farther than its maximum range to reach the identified target. A ranged attack roll made to deliver a seeking spell is not subject to cover or concealment. In order to benefit from this feat, the selected spell must have a range greater than touch and target one or more creatures, or it must require the caster to make a ranged touch attack.
If we look at Fireball, we see:
Area 20-ft.-radius spread
If you attempt to send the bead through a narrow passage, such as through an arrow slit, you must “hit” the opening with a ranged touch attack, or else the bead strikes the barrier and detonates prematurely.
Fireball does not have a target line of one or more creatures, nor does it require the caster to make a ranged touch attack. There are just instances where you need to do so.
An example of a spell where you're required to make a ranged touch attack is Scorching Ray, which states:
Each ray requires a ranged touch attack to hit and deals 4d6 points of fire damage.
A tangent on the usage of Seeking Spell.
If we look at the rules for magic we see:
A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It’s like line of sight for ranged weapons, except that it’s not blocked by fog, darkness, and other factors that limit normal sight.
You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast.
Seeking spell allows us to bypass the requirement of having a straight unblocked path for casting a spell.
This means that spells like Magic Missile or Scorching Ray, could be cast if you have line of sight to a target, but not line of effect. It also allows you to ignore Cover and Concealment with spells like Searing light or Scorching Ray, helping to increase your odds of hitting a creature.