Well if a Divine Tree absorbs an entire planet's kinetic energy, the Chakra fruit would contain 5-C energy. (2.58 * 10^29J)
Though it's probably a lot more than that. Considering divine tree victim planets turn into barren wastelands, it probably also absorbs the energy of an entire planet's core. Which will eventually remove a planet's protective magnetic field, exposing it to harmful cosmic radiations and solar winds.
Using earth as a reference, the earth core has a total heat content of roughly 2 x 10^31J (Table 2.17 from page 109 of Chemistry of the Climate System by Detlev Möller), around 11 times baseline Low 5-B. The rotational KE of earth is insignificant compared to this.
Besides the energy that exists in real life, divine tree absorbs a planet's natural energy and also absorbs energy from living beings, which is another unquantifiable boost to the total energy pool of a Chakra fruit.
A Divine Tree extracting energy of our earth would be at least have 2.0258 x 10^31J (Low 5-B)