library(shinyBS)
library(shiny)
library(DT)
library(shinyjs) ## needed to tamper with the HTML
ui <- fluidPage(
  useShinyjs(),
  # need to include at least one bs element in ui
  bsTooltip(
    "foo",
    "This tooltip goes nowhere - it's there to make the tooltips defined with addPopover on the server side work"
  ) ,
  
  DTOutput("table")
)
server <- function(input, output, session) {
# once the UI is loaded, call shinyBS::addPopover to attach popover to it
session$onFlushed(function() {
    addPopover(session = session,
              id = "DataTables_Table_0",
              title = "information",
              content = "this is the popover on id DataTables_Table_0"
    )
    addPopover(session = session,
               id = "tableRow_3",
               title = "row information",
               content = "this is the popover on id tableRow_3")      
  })
  
  output$table <-
    renderDataTable({
      datatable(data = iris,
                options = list(
                  rowCallback = JS(
                    "function( nRow, aData) {",
                    "$(nRow).attr('id', 'tableRow_' + aData[0]);",
                    "}"
                  )
                ))
            })
}
# Run the application
shinyApp(ui = ui, server = server)

  output$table <-
    renderDT({
      datatable(
        data = iris,
        options = list(
          rowId = JS("function(data){return 'tableRow_' + data[0];}")
        )
      )
    }, server = FALSE)

Thought I'd give one more update (for future reference) before I move on out of reprex territory. 
The below version has <strike>a modified rowCallback function to assign ID's to the cell in the fourth column of each row</strike>.  **Edit**: one more update - using the createdcell function to create the id tags, as suggested by Stéphane Laurent. In the createdcell JS function to the (zero-based) rowindex is increased with 1 to match it with the dataframe row indices for populating content using iris$Petal.Width[row] in a for loop.
In the addpopover() call the option 'container = body' is crucial in order to not make the popover mess up the datatable layout (as a result of plunking the popover div into the datatable).
library(DT)
library(shinyBS)
library(shiny)
library(shinyjs) ## needed to tamper with the HTML
ui <- fluidPage(
  useShinyjs(),
  ## need to include at least one bs element in ui
  bsTooltip(
    "foo",
    "This tooltip goes nowhere - it's there to make the tooltips defined with addPopover on the     server side work"
  ) ,
  
  DTOutput("table")
)
server <- function(input, output, session) {
  
  ## once the UI is loaded, call shinyBS::addPopover to attach popover to it
session$onFlushed(function() {
      addPopover(session,
                id = "DataTables_Table_0",
                title = "information",
                content = "this is the popover on id DataTables_Table_0"
      )
    
      for (row in c(1:nrow(iris))) { 
        addPopover(session,
                 id = paste0('cell_', row, '_2'),
                 title = "cell information",
                 trigger = 'hover',
                 content = paste('petal width =', iris$Petal.Width[row]),
                 options = list( container='body')) # container= 'body' makes it so that the     popover div doesn't scoot over the next column/mess with the datatable lay-out.
      }
    })
  
  output$table <-
    renderDataTable({
      datatable(data = iris[1:10,],
                options = list(
                 columnDefs = list(
                    list(visible=FALSE, targets=3),
                    list(targets = "_all",
                         createdCell = DT::JS("
                                             function(td, cellData, rowData, row, col) {
                                                    $(td).attr('id', 'cell_'+(row+1)+'_'+col); 
                                             }
                                           ")
                              ))))
        }, server = FALSE) #server = F is crucial for addpopover to find the new IDs
}