There is NOTHING in Romans about "total inability". Those are just words from calvinists to prop up their theology.
In fact, Paul clearly indicated how much CHOICE man has.
12 Therefore do not let sin reign in your mortal body so that you obey its evil desires.
13 Do not offer any part of yourself to sin as an instrument of wickedness, but rather offer yourselves to God as those who have been brought from death to life; and offer every part of yourself to him as an instrument of righteousness.
16 Don’t you know that when you offer yourselves to someone as obedient slaves, you are slaves of the one you obey—whether you are slaves to sin, which leads to death, or to obedience, which leads to righteousness?
Paul was teaching about the various choices BELIEVERS have.
To either "let sin reign in your body", or NOT to.
To either "offer yourself to sin", or "offer yourselves to God".
That precedes ch 8. So your interpretation of v.8,9 is quite faulty.