“‘Having conquered the army of the pleasant and agreeable, meditating alone, I discovered bliss,
the attainment of the goal, the peace of the heart. 
Therefore I don’t form intimate ties with people,
nor does intimacy with anyone succeed in my case.’”
does “bodhi” or anu-bodhi imply one is an arahant or stream enterer, or can it be in a relative sense of, for example someone practicing 7sb (awakening factors) contemplating something with relative bodhi value, not yet fully awakened?
Yes, I also don’t know. Anubodha is quite commonly used in the simple sense of “understand, wake up to”, as for example:
There are other principles—deep, hard to see, hard to understand (duranubodha), peaceful, sublime, beyond the scope of reason, subtle, comprehensible to the astute—which the Realized One makes known after realizing them with his own insight.
It doesn’t mean “discover” in the sense of being the first person to find out about something.
No, here bodhi is not the noun “awakening”, but the aorist first person singular, “I awakened” or “I understood”, i.e. “I awakened to bliss”, or less literally “I understood the true meaning of happiness”.
I don’t know if it’s firmly established enough as a technical term to draw definitive conclusions. In this context, it seems to mean becoming a Buddha. However, at MN 95 it is described as stream-entry:
Persevering, they directly realize the ultimate truth, and see it with penetrating wisdom. That’s how the awakening to truth is defined, Bhāradvāja. I describe the awakening to truth as defined in this way. But this is not yet the arrival at the truth.”
Well, it’s not really infamous, but Sylvester knows what I mean! Ajahn Brahm has used it, mistakenly I believe, to claim that the Buddha “discovered” jhana in the sense that no-one practiced it before him. But that’s clearly not what the verb “understands” means; but Ven Bodhi translated it as “discover”, even though I’m sure he didn’t mean it in that sense.
It would fit a normal sutta idiom more easily if it said something like “the Buddha became awakened by means of jhana” or “the Buddha, practicing jhana, became awakened”. Unfortunately it seems hard to construe such readings from the line as it stands. “Jhana” is the direct object of the verb “awaken” so it reads something like “the Buddha became awakened to jhana”, i.e. he fully understood the true significance of jhana. There’s nothing wrong with such a reading, but it’s awkward.
I had this topic saved offline to read later, and just did, so sorry for being late! I also typed this offline before I could read all replies.
This is how I understand it:
eko – literally “one”, nominative.
ahaṃ – “I”, nominative. (junction drops the a)
jhāyaṃ – “meditating”, pretty sure it is an uncommon form of a present particle, nominative. It is from the verb jhāyati which has a wider meaning than “doing jhāna”, as you have it.
sukhaṃ – “pleasure”, accusative. Not part of a compound verb as you seem to interpret it, but a junction turned the ṃ into m. So this is a separate word.
anubodhiṃ – “I woke up (to)”, 1st person sg. past tense (aorist) of anubujjhati, as Ven. Sujato said. Anubodh-iṃ equals anubujjh-iṃ through some sort of assimilation, which I’m not an expert in. See AK Warder L23.
So if you put it together: "one I, meditating, to pleasure woke up."
Or: “meditating alone, I woke up to pleasure.”
The meaning seems to be that the Buddha realized what real pleasure is, “the attainment of the goal, the peace of the heart”, i.e. the extinguishment of the defilements, nibbāna. Bhikkhu Bodhi translates it as “discovered”, which makes it a bit more fluent. In a sense this discovery is made by every enlightened being, so I don’t mind his translation.
This enlightenment happens outside of jhānas (I know this is a bit controversial, but that’s how I see it) so it’s best not to translate jhāyati as “do jhāna”, which, as I said, it doesn’t really mean, anyway. The sukha quite obviously also doesn’t mean the pleasure of jhāna, but the ‘pleasure’ of (pari)nibbana.
Whether the Buddha discovered the jhānas is another matter. I don’t know. But he surely discovered their importance.
No pali scholar but could this mean ‘I practice alone, having discovered the bliss of awakening’? Saccānubodhoda is from MN95, reminded me of sattya avabodha in sinhalese meaning realization or attainment of Nibbana. I suppose it could mean stream entry or higher attainment.
We know the Buddha preferred solitude and I suspect so would any awakened individual. He does this because his bliss is greater than that derived from sensory pleasures. People are a ‘thorn’ as would be a loud commotion (that sutta).