Rory, The verse you give is in Irish Gaelic, and definitely says My heart is rising (not "my belt") not for the fiddler ... but for the helmsman of the boat ...

but the Scots Gaelic verse also uses a different preposition, ...not from the fiddler or the harpist but from the helmsman of the boat...
And in Scots Gaelic "my heart" is spelled "mo chridhe"
In Irish "crios" (belt, mo chrios = my belt) and "croí" (emphatic, croí-se; my heart, mo chroí-se) look very similar although they are pronounced quite differently.

Scottish Gaelic sound files for cridhe vs
crios

The Scottish version is the older of the two (though I think there are some verses or lines which are shared with other songs which may have been of Irish origin). And perhaps some Scottish singers would also have sung a different version of verse 9 using the words "mo chridhe".