Rooney scored his first goal since March in Manchester United's win over West Ham last weekend and Capello says he was impressed by the application of a player who failed badly during the World Cup finals.
Rooney was also targeted by disgruntled fans in England's friendly against Hungary in August but Capello believes the striker is ready to once again win over supporters of the national side.
"I monitored him during the last game that he played against West Ham," Capello said. "He's good, he's back and I'm happy because he scored a goal. Rooney runs a lot around the pitch, he's free to move where he decides to go. Rooney will play tomorrow in style."
It is reported that Capello is considering utilising Rooney as a lone striker against Bulgaria, with captain Steven Gerrard playing in an advanced role behind him, and the England boss says he has not fully settled on his starting XI.
However, he does expect Phil Jagielka to play at centre back alongside Michael Upson, despite the Everton star missing a number of training sessions with the England squad.
"The keeper, [Joe] Hart, Rooney, Steve [Gerrard], [Gareth] Barry, [Ashley] Cole, [Glen] Johnson, Jagielka, more or less. I know ten or 11, with a little doubt about one,'' Capello said.
"The training was really good, the players are okay and some problems we had in the last two days are getting better. [Jagielka] is fit, he trained well, there is a little bit of pain but I think for tomorrow [Friday] he will be 100%.
"I'm not concerned but I know that the central defenders will play for the first time together tomorrow. I hope they will be really focusing every moment of the game and I hope Cole and Johnson will help these two players, and also the midfield."
England fans voiced their discontent with the underperforming World Cup players when the country struggled to beat Hungary in August's friendly, while certain elements of the national press have been heavily critical of the coach in recent weeks.
However, Capello says he is equipped to deal with whatever criticism comes his way. He said: "This is the job of the manager. When you win, you're the best. When you lose, you're the worst."
Capello's decision to exclude David Beckham from his future plans was particularly attacked by the press and the Italian appeared to backtrack recently when saying that the LA Galaxy midfielder may still be in contention. It is a theme he was asked to revisit in Thursday's press conference.
"The door is still open for all the players, always," Capello said when asked about the prospect of Beckham playing for England again. "If I prefer for this moment to choose young players. But the door is open for other players."
England visit Switzerland on Tuesday for their second qualifier and captain Gerrard believes a strong start is essential after a poor World Cup campaign that culminated in a 4-1 defeat to Germany in the second round.
"The players and the manager realise that we are under pressure at the moment, which is normal after underperforming at the World Cup,'' Gerrard said. "It'll really help if we put in a good performance tomorrow and get the maximum points. Then we can obviously take the confidence from that into the Switzerland game on Tuesday.
"It's very important that we make a statement and show that we want to win the group and qualify comfortably. We qualified for the World Cup playing good, attacking football. If we can perform at that level I'm sure we'll get out of this group in similar fashion.
"The difficult thing is there's slightly more pressure on us this time around and we have to cope with that. We've certainly got the exciting players in the squad to get off to a good start.''