The audience peaked at 9.7m when the winner was announced at 21.55GMT. Two other peaks occurred when One Direction (9.1m) and Adele performed (9.2m).
Last year's average audience for the results show was 9.1m but this included +1 figures.
X Factor's Saturday show was watched by an average of 5.9m.
In recent weeks, the X Factor has struggled to get past the 7 million mark, dipping to 6.71 million for last week's semi-final.
The ITV show has consistently been beaten by BBC One's Strictly Come Dancing this year.
Sunday's Strictly semi-final results show, which saw Anita Rani eliminated, was seen by an average of 10.8m.
The audience peaked at 11.7m.
Next week's final will see The Wanted singer Jay McGuinness, BBC Proms and Radio 3 presenter Katie Derham, EastEnders' Kellie Bright and former Coronation Street star Georgia May Foote compete for the Strictly crown.

The uncapped duo will start Saturday's Six Nations match at Twickenham.
"They don't lack for enthusiasm and they are both incredibly excited about the stage they're going to be playing on," said the Ireland head coach.
Schmidt said it was a "tight decision" whether to name McCloskey or his Ulster team-mate Luke Marshall at centre.
Both have impressed at provincial level this season, forming a dynamic midfield partnership for Les Kiss' side.
"Luke has been robust and had a really good season, but Stu spent last week training at 12 with us and we felt he might be a little bit more comfortable in there," said Schmidt.
"He has some important elements in his game which we want to get the most out of and it's a great opportunity for him to express himself.
"It's also a responsibility to make sure that we are as watertight as we can be in what will be a tough area to defend.
"The bottom line is we have confidence in Stu and Robbie (Henshaw) in there."
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Schmidt is also excited by the prospect of Leinster flanker Josh van der Flier making his debut, with Connacht's second row Ultan Dillane also expected to earn his first cap off the bench.
"We are all excited by something new," said Schmidt.
"Josh has an opportunity to go and really capture that seven jersey in what will be a really tough test for him.
"This is a step up that they haven't been to before and you never know how quick it's going to be, how physical it's going to be.
"That's always a challenge for players coming in for the first time and these guys have been rewarded with the opportunity."

Police were called to Ridley Road in Dalston at about 14:10 BST following reports of shots being fired.
Armed officers found a man in his 30s with a gunshot wound to his leg. He was taken to hospital and is said to be in a "serious but stable" condition.
Police searched the area and recovered a firearm. They also made 13 arrests for a variety of offences.
Ridley Road has been closed while the police carry out their investigation.
The X Factor results show was watched by an average of 8.4m on Sunday, an improvement on recent ratings but still down on last year's final figure.
[NEXT_CONCEPT]
Ireland coach Joe Schmidt says he has gone with "form and balance" in picking debutants Stuart McCloskey and Josh van der Flier to play against England.
[NEXT_CONCEPT]
A man has been shot in the leg and 13 people arrested following an incident in east London.