If I have a temporary unit on a battlefield but it would die on my turn, do I still get the hold point first or not?

No, you do not get the Hold point if you have only a Temporary unit and do nothing in response.

Here's why: the Beginning Phase has two steps — Beginning Step (where "at the start of Beginning Phase" effects like Temporary trigger) followed by the Scoring Step (where Hold points are awarded) (Rule 315.2). The Temporary trigger fires and resolves during the Beginning Step, killing the unit before Scoring happens. Without any units left at the battlefield when control is checked, you lose control during cleanup and do not hold anything to score.

However, you can keep the point if you react to the Temporary trigger. If you play a unit from Hidden or with Ambush (as a Reaction to the Temporary trigger on the chain), your new unit enters the battlefield before the Temporary kill resolves (LIFO order). You maintain unit presence and successfully score the Hold point in the Scoring Step (FAQ #9983, FAQ #6741).