You may give reference link to their site, and their branding in characters. You may not be allowed to use their logo on your site. Their lawyer may contact and demand you to take the logo down in future.

Great to hear that. Thank you for clarifying.

Also, one more ques, can I use the Booking.com logo while showing the hotel reviews to the users, since its their users ?

Crawling a website is absolutely legal.
As long as no security barriers had to be circumvented.

It is at maximum an AGB violation if an account had to be used.