The governing body took the decision to switch the club's membership to OK Bulls Ltd after Khan's group bought the club from the administrators in August.
Bradford's membership was suspended in June when they entered administration.
"The board's decision closes the door on much of the uncertainty that has surrounded the Bulls in recent months," RFL director Blake Solly said.
"The club's new owners have co-operated fully with the RFL throughout this necessarily extensive process and we look forward to working with Mr Khan and Mr Sutcliffe in the months and years ahead.
"The decision to grant membership is an important step that will help the board to determine which competition Bradford Bulls will compete in from 2013."
No decision has yet been reached on what division the Bulls will compete in next season but an announcement is expected by the end of the week on how that decision will be reached.
Bradford finished ninth in Super League this season, three points outside the play-offs, having been deducted six points for entering administration.

The case revolved around a horn "hit", which was allegedly lifted from the Salsoul Orchestra track Love Break.
But the US 9th Circuit Court of Appeals said the sample lasted less than a second, and would not have been recognisable to the general public
"Without careful attention, the horn hits are easy to miss," it said.
Producer Shep Pettibone worked on both Vogue and Love Break. The one-note horn sequence in contention lasted just 0.23 seconds, the court heard.
You can hear the original at 4'40" in this clip, and at 1'02" in Madonna's track.
"After listening to the recordings," wrote judge Susan P Graber, "we conclude that a reasonable jury could not conclude that an average audience would recognise the appropriation of the composition".
However, the court's decision was not unanimous, with Judge Barry G Silverman arguing that the uncredited sample, if proven, would amount to theft.
"It is no defence to theft that the thief made off with only a 'de minimis' part of the victim's property," Silverman wrote.
He said a copyright of a recording amounted to a "valuable property right, the stock-in-trade of artists who make their living recording music and selling records".
The ruling could lead to short samples becoming more commonplace.
However, as The Hollywood Reporter points out, the California court's decision directly contradicts a 2006 case presented in the 6th Circuit (Tennessee).
That revolved around an NWA song that sampled a riff from George Clinton's band Funkadelic. At the time, a 6th Circuit judge wrote: "Get a license or do not sample. We do not see this as stifling creativity in any significant way."
The takeover of Bradford Bulls by Omar Khan's consortium has been ratified by the Rugby Football League.
[NEXT_CONCEPT]
Madonna's Vogue did not break copyright law, even though it contained a snippet of another artist's song, a US court has ruled.