Syria's military and Russia carried out more than 100 air raids in Idlib, Hama and Aleppo provinces, the Syrian Observatory for Human Rights said in a statement.
The Observatory said dozens of barrel bombs were dropped by Syrian military helicopters.
Three women and one member of the White Helmets - a team of first responders working in some rebel-held areas - were also among the nine dead, the war monitor said.
All nine civilians were killed in Idlib and Hama, it said.
The first responder was killed after arriving at the site of raids to treat people wounded in southern Idlib, the head of the White Helmets Raed Saleh said on Twitter.
An AFP photographer saw clouds of black smoke above two villages in southern Idlib after the air raids.
Syrian state news agency SANA said the country's military had opened fire on "terrorist groups".
Much of Idlib and parts of Aleppo and Hama are controlled by Hayat Tahrir al-Sham (HTS), al-Qaeda's former Syria branch.
The regime has intensified airstrikes against these areas in recent months, despite a September deal between government ally Russia and rebel backer Turkey that is meant to protect Idlib from a massive regime offensive.
Syria's multi-fronted civil war has killed more than 370,000 people and displaced millions since it began in 2011 with anti-regime protests that sparked a devastating crackdown.
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