What? No! Turn the water off to the sink and don’t use the sink for 24hrs while the sealant dries but that’s it. Who told you whole house?

No. A strapped sink with slight positive reveal can be used an hour after installation.

Thanks for your replies. The person I worked with at cabinet store told me I’d have to turn off all water, but contractor said he had not heard this.

That sounds crazy!

" The person I worked with at cabinet store told me I’d have to turn off all water, "

Would make me wonder what other tidbits of misinformation he gave you.