Is it permissible to pay the value of a radio taken from its deceased owner to a needy person with the intention of charity on behalf of the owner, and would that absolve the one who took it?

You must repent to Allah for taking other people's property, and return the radio or a similar item or its value to the heirs of its owner. If you cannot find them, then donate its value on his behalf, and increase in acts of obedience and supplication for the owner of the device.