CIP requires you get a name, number (passport will do), address and DOB.
If the account is interest bearing, the Internal Revenue Code requires you to get a W-9 or its equivalent from a U.S. Person or a W8-BEN or its equivalent from a non U.S. person.
The W8-BEN is not connected to CIP. It fulfills separate, unrelated requirements of the IRC.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.