After scoring an unbeaten century for New South Wales at Under-19 level in 2007, Osborne made her WNCL during the 2008–09 season.

Australia stayed for a bilateral series against the hosts, and Osborne was dropped after going wicketless in the first two ODIs and being required to bowl less than half of her overs; she was also overlooked for the one-off Test.

Osborne was selected for the Rose Bowl series at the end of the season but had limited opportunities because of the presence of Sthalekar and Nitschke.

In the match against Western Australia, she hammered an unbeaten 106 as New South Wales amassed 3/305 before dismissing their opponents for 35.

She took 2/13 from ten overs in the first match, helping to restrict Queensland to 9/108 before New South Wales completed an eight-wicket win.

[4] Osborne ended the WNCL season with 16 runs without being dismissed and took 15 wickets at 14.20 at an economy rate of 2.47 from eight matches.

[5][6] Osborne was rewarded with her first international call-up ahead of the 2009 Women's Cricket World Cup after leading the wicket-taking in the WNCL.

[4] She was included in the team for the opening match against New Zealand at North Sydney Oval, taking 2/37 from her ten overs as Australia conceded 205.

She then claimed 1/35 from ten overs in Australia's must-win match against South Africa as the hosts avoided elimination with a 61-run victory.

She then batted in the World Cup for the first time, in last group match, before taking 2/22 from ten overs as Australia defeated West Indies to reach the next round.

Osborne was not required to bat as the Australians won both matches but it was not enough to place them in the top two nations and qualify for the final.

The hosts were all out for 142 and India reached the target with three wickets in hand despite Osborne's economical return of 2/21 from nine overs.

[4] Osborne ended the World Cup with nine wickets at 19.77 at an economy rate of 3.01; in all but one match, she was more economical than the Australian team as a whole.

[4] Osborne was selected for the 2009 World Twenty20 in England and Australia hosted New Zealand for three T20 matches in tropical Darwin during the southern hemisphere winter before the teams flew to the tournament.

She was played in the first two ODIs held at Ford County Ground, Chelmsford, taking a total of 0/39 from eight overs and making 1 and 11 not out in comfortable English victories by nine wickets and 53 runs.

She then took 3/33 from nine overs to help dismiss Victoria for 147, sealing a fifth consecutive title and was named the player of the match for her contribution.

In seven matches, all of which were won, she was used mostly as a batsman, often batting in the top-order and was largely rested from her bowling duties, delivering only nine overs in total.

[4] In the middle of the season, she played for the Australian Under-21s against New Zealand Emerging Players in five matches, and allowed to bat higher up the order in the youth team, she made 129 runs at 129.00, scoring 48 not out and 60 in the last two games.

Her best performance in the field was her 3/25 and two catches in the fourth match, which in addition to her unbeaten 48 helped Australia to a series-sealing 122-run win.

[4] Osborne was selected in the Australian squad for the Rose Bowl series against New Zealand, but was not fully utilised in the first two matches at the Adelaide Oval, as captain Alex Blackwell elected to use Sthalekar and Nitschke more often and earlier.

[4] In the five T20s that followed, three at Bellerive Oval in Hobart, and two in New Zealand, Osborne only played in the fifth match, taking 1/13 from two overs and scoring one as Australia were bowled out in a 17-run defeat and lost 5–0.

In the run-chase she made 13 not out at the death as Australia reached the target with two wickets in hand from the final ball.

[4] Osborne was part of the 2010 World Twenty20 winning team in the West Indies but played in only one of Australia's matches.

Elliott was required to neither bat nor bowl as the Indians ended with 3/119, which was chased down by the Australians with seven wickets and seven balls to spare, and was retained for the final, making 19 not out from 20 Australia won by three runs in a low-scoring match.