I know what it calls for and I understand what 1 means, but some are into overkill. I run payroll for a multitude of companies, and I send them the forms for I-9 verification. I won't do it for them, but I will store al of their documentation on our server in their files. In general, I get everything from their license, their SS card, passports, you name it.
Most folks do not mind.
Regardless if folks don't mind it is as simple as this.
The legal form made by the US Government states there is a choice of providing 1 document from section A or 1 document from B and 1 from C.
It states the the employer can not force such choice of what document the company will accept.
It also states the employer is to examine the document(s) and not anything about storing them.
The employer is supposed to "review the items" you are not required to make copies of the employee's documents for storage and I personally would not allow that.
Only the form is legally required to be retained which of course has the ssn but in my opinion you should not be storing copies of any of the documents used to verify the employee's status and again I would not consent to that.
"Employers must
examine the employee’s documents and record the document information in Section 2."
"Employers must retain all completed pages of Form I-9 for a designated period and make them available for inspection by authorized government officers."
"ANTI-DISCRIMINATION NOTICE: All employees can choose which acceptable documentation to present for Form I-9. Employers
cannot ask employees for documentation to verify information in Section 1, or
specify which acceptable documentation employees must present for Section 2 or
Supplement B, Reverification and Rehire."