One potential prooftext for the deity of Christ is Rom 9:5. Bruce Metzger wrote a classic essay on that years ago ("The Punctuation of Rom 9:5"). Unfortunately, it has never been posted on the internet. Here's a more recent, albeit brief, defense of the same interpretation:
It is possible that Paul concludes his description of the Israelites (Rom 9:4-5) with his third set of privileges after using the workgroups "of whom adoptive sonship…", "of whom the fathers," and "from the whom the Messiah…", and then, after a major stop, praises God for what he has done. This does not seem to follow Paul's logic of his argumentation at this point, however. Paul is not intent on praising God for what he has done, since he has just recounted his own agony over his people. Instead, Paul recounts the privileges of the Israelites, which have culminated in his noting that they are the line from whom the Christ has come. If there is praise to be given, it is praise of this Christ. Paul praises him as the God who is above all things, blessed for eternity. These two elements–having the divine nature that places him positionally over all things, and being blessed forever–are both reflective of statements that are often attributed to God. God's position of being over all things is firmly established since Genesis 1 in the OT, and the term "blessed" (cf. Rom 1:25), with God being "blessed unto the ages") is one that is often used to describe God himself (e.g. Gen 14:20; 24:27). Paul's rising crescendo regarding the privileges of Israel are fittingly capped by his proclamation that they themselves are responsible for the earthly origins of the Messiah who, as Paul has already established even in the letter to the Romans, functions as one with God, and is, in fact, the God over all things and is to be blessed. S. Porter, The Letter to the Romans: A Linguistic and Literary Commentary (Sheffield Phoenix Press 2015), 183-184.