Middle Set on Coordinated Board vs Maniac

[DonkeyDonk]

Playing in a live home game with quarter/half blinds, two players limped in and with $48.50 behind, I called with 3c 3d. A loose maniac to my immediate left called, as did the blinds, making us 6-handed to the flop.

Flop ($3): 2h 3s 5s

The blinds checked, UTG bet $1, the next player called and I made it $5 total with middle set. The maniac called and everyone folded.

Turn ($15): 9s

I bet $8 and the maniac sighed heavily. After a pause, he pushed in, covering me ($35 left and almost 2-to-1 pot odds). About a month ago, I was involved in a hand with the maniac where I had top pair in an unraised pot, and bet the flop and turn OOP. The maniac called me on the flop and sighed heavily before calling the turn (setting off alarm bells in my head). Luckily, a scare card came on the river and I check-folded when the maniac made an obvious value bet. He conceded afterwards that he filled his gutshot on the turn.

The maniac is well-known for pushing with ATC though, and has shown some audacious, winning bluffs this session by pushing in with air. What's the best action to take?