'will have opened' is a correct and usable part of a sentence in written English.
You could use it in a sentence such as: "By the time the party starts, the restaurant will have opened."
By 2002, five new car factories will have opened in Brazil, in addition to Renault's.
By the middle of next year, the two will have opened an Umami Burger in lower Manhattan.
If such results are confirmed by future studies, a new front will have opened in the war on cancer.
Whatever success the Party enjoys in the upcoming elections, it will have opened new avenues of participation for India's small and struggling independent parties.
It will have opened in nearly all major territories by New Year's Day; aimed rather unerringly at the Golden Globe/Oscar voters, as well as holiday audiences.
By mid-July, Mr. Leonard will have opened another 10,000-square-foot 10,000-square-foot 10,000-square-footve tastore bars and offer educatinnal events daily.
Two months after having a pacemaker implanted, Ted Williams will have open-heart surgery today in New York.
Workers with ten years or more of service will have open-ended contracts and companies will have to inform unions before sacking anyone.
The cafe at the entrance will have open-air seating in good weather, and the restaurant connects to a nightclub and lounge.
Other Web-based news sites will provide similar coverage, and NationalJournal.com, normally open only to subscribers, will have open access for the conventions.
Newly-elected UKIP councillors will have "open minds" about local politics, he added.
