Acorns cannot DRS transfer, but they can transfer to another broker for a $50 fee. A popular choice has been Fidelity, who can DRS transfer for free, and quickly. Fidelity have also been known to reimburse the transfer fee if asked (up to $75).
Acorns to Fidelity Route:
Open an account with Fidelity. When it asks you how you want to fund your account, select transfer from another brokerage. Fidelity will pull your shares from Acorns. This will take roughly 3 days. From there you can follow the Fidelity guide located here.
For more information on transferring out of Acorns, you can read their support page on it here (It says funds in the title, but goes on to talk about shares).