Is Na$^+$ more stable than Na?
I think you are mixing things up in your question and it would be helpful to specify what the question in your textbook was.
NaCl is a solid made up from Na$^+$ and Cl$^-$ ions, not from uncharged atoms as stated in your question,  arranged in a periodic crystal lattice. So the redox equations for oxidation and reduction in your question are not relevant for the formation of NaCl from its ions e.g. from a supersaturated solution, where the formation of the solid releases lattice energy. Although the redox equations are relevant, when looking at the formation of NaCl$_{(s)}$ from its elements Na and Cl, which you rightly pointed out yield the favorable noble gas configuration for both. (See Born-Harber cycle for more information on the formation of salts from its elements and the related energies)
As stated in Nilay Ghosh's comment, a question (and answer) comparing the stability of Na vs Na$^+$ can be found here.
Also: Sodium ions do in fact react with other (uncharged) atoms, it's just a question of a strong enough reducing agent under the right environment. Commercially, sodium was produced in the Deville process at 1100 °C with carbon as the reducing agent:
$\ce{Na2CO3 + 2 C -&gt; 2 Na + 3 CO}$