Since Shakespeare never shows Othello in any military situation (most of the scenes in the play would be considered domestic), we must take what others say about him as our textual proof that Othello is or is not "a heroic soldier."
In Act I, scene iii, when Othello enters the signiory, the Duke of Venice greets him with:
Valiant Othello, we must straight employ you,
Against the general enemy Ottoman...
suggesting that, first, he considers Othello valiant and, second, though Othello is not a Venetian, the duke considers him the only man for the job of fighting the Turks on behalf of Venice. And later, the Duke all but tells Othello that he must not consider taking a honeymoon with Desdemona, because:
The Turks with most mighty preparation makes for Cyprus: Othello, the fortitude of the place is best known to you, and though we have there a substitute of most allowed sufficiency, yet opinion, a sovereign mistress of effects, throws a more safer voice on you...
And with these lines, the Duke, a disinterested voice in the play (and the most exalted) pronounces that he, along with the voice of "opinion" considers Othello the most qualified and best man to face the Turks. And true to the Duke's faith, Othello earns an easy victory in Cyprus, further cementing him as a noble and heroic soldier.
It is also important for the tragic progression of the play that Othello be seen as a "heroic soldier" in the beginning of the play. His demise as the tragic hero of the play is much more pitiful and heart-wrenching, two important criteria in a classic Tragedy, if he begins from a very high place, falling from his position of power and authority because of his tragic flaw.
So, based upon the word of the Duke of Venice and the requirements of a classically Tragic plot, yes, I agree. "Shakespeare presents Othello as a heroic solider."