For the Kremlin, the growing ferment among Russians who in nine months’ time will be eligible to vote in their first presidential election is an added headache as the 64-year-old leader seeks to extend his almost two-decade-long rule. Putin’s approval ratings remain sky-high, but his political managers are worried they will struggle to deliver the commanding victory and high turnout that the Kremlin is seeking to cement his control for another six-year term, according to people involved in the effort.

Many young people are less wedded to the Putin model than the rest of the population, having spent their lives in a period of relative prosperity without major upheavals, unlike their parents’ often-wrenching experiences in the 1990s, according to pollsters.

“The young are less worried about stability and more interested in change,’’ said Alexei Grazhdankin, deputy head of the Levada Center polling company in Moscow.