Provide your developers access to the Dev Hub and Salesforce DX development tools by adding a user with Salesforce Limited Access - Free license and the Limited Access user profile in your Dev Hub org. Then create and assign them a permission set to the required Dev Hub objects.
Before You Begin
The Salesforce Limited Access - Free is designed for users whose role is to build customizations or applications. This license provides access to the Dev Hub, development tools, and environments. In the production org, this license restricts access to standard and custom objects.
Create a user in your Dev Hub org.
In Setup, enter Users in the Quick Find box, then select Users.
Click New User.
Fill out the form.
Select Salesforce Limited Access - Free for User License, and then Limited Access User for Profile.
After filling out the remaining information, click Save.