Even though a 9 makes a straight I lead here 100% of the time.

I usually bet $1/$2 less than the pot on the flop/turn. Pot $5 on flop I bet $4, A HU pot will be $12 and change after the rake on the turn so I bet $10. Dunno how I came up with those originally but it's how I play. In reraised pots I often overbet(see: push) very good hands though or bet just less than pot on flop and overbet/push the turn.