No, the spherical shape of planets has not always been present since their inception. Planets, like other celestial bodies, undergo a process called accretion during their formation. Accretion is the gradual accumulation of mass through the collision and merging of smaller objects, such as dust particles and planetesimals, under the influence of gravity.
Initially, during the early stages of planetary formation, the matter in a protoplanetary disk is distributed in a relatively chaotic manner. Over time, however, the force of gravity causes the matter to coalesce and form larger and larger objects. As these objects grow in size, their gravitational pull increases, attracting more matter towards them. Eventually, the process leads to the formation of planet-sized bodies known as protoplanets.
As protoplanets continue to accumulate mass, their own gravity causes them to become more spherical in shape. This is because gravity acts equally in all directions, pulling material towards the center of mass. The self-gravitational force eventually overcomes other forces, such as structural strength, and shapes the protoplanet into a roughly spherical shape.
Therefore, the spherical shape of planets is a result of the evolutionary process of accretion and gravitational forces acting over long periods of time. It is not an inherent property from their inception, but rather the outcome of the dynamic processes involved in planetary formation.