As I understand it, the sutta indicates in the beginning that the first meditator described is meditating with a mind obsessed with the hindrances. The second meditator described is the arahant in the meditative experience of nibbāna.
What leads me to think that an awakened one is intended here is the verse following the section on the one who meditates without dependence. Purisuttama , highlighted below, here and elsewhere refers to an arahant. (see also DN 32, SN 22.79, Snp 3.6)
"‘Homage to you, O thoroughbred person!
‘Namo te purisājañña,
Homage to you, O supreme person!
namo te purisuttama ;
We ourselves do not understand
Yassa te nābhijānāma,
What you meditate in dependence on.’”
yampi nissāya jhāyasī’”ti.
For example, SN 22.79 describes what, from the context of the sutta, is clearly an awakened one and uses the exact same verse:
“When, bhikkhus, a bhikkhu is thus liberated in mind, the devas together with Indra, Brahma, and Pajapati pay homage to him from afar:
“‘Homage to you, O thoroughbred man!
Homage to you, O highest among men [ purisuttama]!
We ourselves do not directly know
Dependent upon what you meditate.’”
So it seems to me that it’s describing the meditative experience of nibbāna, fruition attainment for the arahant (this state being one without dependence of any kind).
To echo what @suaimhneas said, I think all meditators must meditate in dependence on something until they reach the state of no-dependence (i.e., nibbāna). In other words, consciousness is dependent on name-and-form until that dependence is cut with the attainment of nibbāna.
The first type of meditator is described as a “wild colt”, which I take to mean that they are as yet untamed, still immature in their development (and thus subject to hindrances). The “thoroughbred”, on the other hand, is fully tamed and mature. I see this sutta as the Buddha encouraging Sandha, who he might have felt was ripe, to direct his mind toward nibbāna.