The trustee has the power to pay any sum of principal or income distributable to a beneficiary, without regard to whether the beneficiary is under a legal disability, by paying the sum to the beneficiary or by paying the sum to another person for the use or benefit of the beneficiary. Any sum distributable under this section to a custodian under the California Uniform Transfers to Minors Act (Part 9 (commencing with Section 3900)) shall be subject to Section 3906.