The variation is almost forced if White aims for the standard Smith-Morra setup. At the end White is a pawn down and no longer has two bishops, but is well developed. However Black's setup does not seem to have any weaknesses that can be pressured by White's superior pieces.
White's most immediate plan is to strike on the flank with a4, provoking ...b4.
In most of games at 2000+ level, White ends up defending a worse endgame.
[fen ""]
1. e4 c5 2. d4 cxd4 3. c3 dxc3 4. Nxc3 e6
5. Nf3 Nc6 6. Bc4 a6 7. O-O b5 8. Bb3 Na5
9. Re1 Nxb3 10. Qxb3
If Black reveals his intention to play ...a6 early, White has alternative plans: Play Bf4, threatening Nd5 with pressure on the dark squares c7, d6 and b6, leading to decent games with White retaining the initiative. So Black should delay ...a6 as much as he can, as Bf4 only makes sense after ...a6.
[fen ""]
1. e4 c5 2. d4 cxd4 3. c3 dxc3 4. Nxc3 Nc6
5. Nf3 a6 6. Bf4 e6 7. Be2
Also, ...Na5 needs to be played immediately, as 8...Bb7 allows 9. a4 with initiative and nasty tricks from White. Example game:
[fen ""]
[White "Vivante-Sowter, John (2259)"]
[Black "Kavc, Andrej (2270)"]
1. e4 c5 2. d4 cxd4 3. c3 dxc3 4. Nxc3 e6 5. Nf3 a6 { B21 Sicilian Defense: Smith-Morra Gambit Accepted, Kan Formation } 6. Bc4 b5 7. Bb3 Bb7 8. O-O Nc6 9. a4 b4 10. Nd5 Na5 11. Bg5 f6 12. Ne5 Bxd5 13. exd5 Nxb3 14. dxe6 dxe6 15. Qxb3 Qd5 16. Nc4 fxg5 17. Rad1 Qf5 18. Rfe1 Bc5 19. Nd6+ Bxd6 20. Rxd6 Nf6 21. Rdxe6+ Kf8 22. Qxb4+ Kf7 23. Qc4 Kg6 24. g4 Qf3 25. R1e3 Qd1+ 26. Kg2 Rad8 27. Rxf6+ gxf6 28. Qe4+ Kf7 { The game is a draw. } 1/2-1/2