Hello, welcome to JustAnswer, my name is Judith. Thank you for this opportunity to answer your questions.

Yes, you must have an I-9 on each and every employer.

You cannot back date them.

There are civil and
criminal penalties for hiring illegal aliens. Sec. 274A of the Immigration and
Nationality Act (INA) and 8 U.S.C. 1324a, makes it unlawful for any person
knowingly to hire, recruit or refer for a fee any alien not authorized to work.
An employer that violates these laws can face penalties of:

• $2000 to $5,000 fine for each unauthorized
  individual;


• $2,000 to $5,000 for each employee if the
  employer has previously been in violation; or


• Two (2) strikes and the employer is out

The employer could also be fined $1000 to $25,000 for each individual "paperwork"
violation.

The criminal penalties
for a pattern and practice violation is $15,000 for each unauthorized alien,
imprisonment of not less than one year, or both.

Judith

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