Hi blowfly - it's always nice to post the full clues, numbers of letters & any you've placed, so that people without the puzzle can more readioly help you - thanks for next time! :-)
That said -
1a First of burners turned on, so warmer? (6) - Brandy - b(urners) + 'randy' (turned on)
9a What's odd about river? It's Britain's longest (6) - Severn - 'seven' (odd [no]) (about) r(iver)