Rashevsky is a late bloomer and is unlikely to have the NHL impact of Kaprizov or Panarin. But he's been legitimately good in the KHL this year, at the age of 21.
Age 21+ season in the KHL
Rashevsky (9 Oct 2000), 2021-22: 9 goals + 5 assists = 14 points (15 games)
Kaprizov (26 Apr 1997), 2018-19: 30 goals + 21 assists = 51 points (57 games)
Panarin (30 Oct 1991), 2012-13: 11 goals + 8 assists = 19 points (43 games)
Shipachyov (12 Mar 1987), 2008-09: 4 goals + 4 assists = 8 points (29 games)
Rashevsky's goals per game (0.6) and points per game (0.93) are slightly higher than Kaprizov (0.53 GPG, 0.89 PPG) -- though on a much smaller sample size so far -- and much higher than Panarin or Shipachyov.
From the chart
@surixon posted above, only Tarasenko (14 + 18 = 32 points, in 31 games) has put up more points per game than Rashevsky in a KHL season before the age of 22, and even then Rashevsky's goal-scoring pace is better.
It's still early, but Jets fans have every right to be excited by Rashevsky's production this year, especially when so many of his points have come on highlight reel plays.