Regarding your question do the Vedic histories refer to this planet only. No. Vedic history means of this universe. Our history begins from the beginning of the creation because the creation takes place with the birth of Brahma from the abdomen lotus flower of Lord Visnu. Then Brahma gradually creates. He begets so many sons known as Prajapatis who are supposed to be the generators of living entities, and therefore the history begins from Brahma. In the Bhagavad-gita this is confirmed in the 15th chapter. It is said there that the root of this big universal banyan tree is on the top; therefore history begins from the top.
Yes. This planet comes later on. We can take the idea from the tree—the tree grows gradually, and the different fruits, branches, and twigs gradually appear. Therefore it is to be understood that this planet has grown later on. Besides this we understand that although the planet was later on grown up, it was covered with water—pralaya payodhi jale **, merged into the water after devastation. Then gradually it emerges from water. That we can experience, that gradually land is coming out of the oceans. Because of its being merged into water, it is natural to conclude that the beginning of life was aquatic. This is confirmed in Padma Purāṇa that the species of life evolved from aquatics to plants, vegetables, trees; thereafter insects, reptiles, flies, birds, then beasts, and then human kind. This is the gradual process of evolution of species of life.
But we do not accept Darwin's theory. According to Darwin's theory, homo sapiens came later on, but we see that the most intelligent personality, Brahma, is born first. So according to Vedic knowledge, Darwin or similar mental speculators are rejected so far the fact is concerned.