pearl river cruise

Hello my partner and I will be in Guangzhou on May 30 this year. We really want to do the river cruise but have to be back at the airport by 10.00pm at the latest. I think the 6.40 option from Tianzi Wharf looks suitable. Does it take about 90mins? Does it return back to Tianzi Wharf? Will there be (reputable) taxis available to take us directly to the airport after the cruise? Can we book online before we get there or is just as easy to book on the day? Thank you Drew M