[Solved]-R Highcharter: Formatting dual y-Axis chart-Highcharts

Figured it out! I can put the max in the hc_yAxis_multiples and in hc_plotOptions, instead of using series, I use column.

highchart() %>%
            hc_yAxis_multiples(list(title = list(text = "%, OTD"),lineWidth = 0, labels = list(format = "{value}%"), max = 100), list(title = list(text = "Qty, Volume"), opposite = TRUE)) %>%
            hc_xAxis(title = "Sites", categories = paste0(SiteOTD$Plant.Name,"-",SiteOTD$SBU), labels = list(step = 1, rotation = -60, style = list(fontSize = "1.0vh"))) %>%
            hc_add_series(SiteOTD, "column", hcaes(x = Plant.Name, y = round(OTD,2)*100), name = "On Time Delivery", yAxis = 0) %>%
            hc_add_series(SiteOTD, "line", hcaes(x = Plant.Name, y = Shipments), name = "Volume", marker = "diamond", color = "#FF7900", yAxis = 1) %>%
            hc_tooltip(crosshairs = TRUE, headerFormat = "<b>{point.x}</b><br>") %>%
            hc_legend(enabled = FALSE) %>%
            hc_plotOptions(column = list(colorByPoint = TRUE, colors = SiteOTD$Colors))

This removed the functionality of shared = TRUE in hc_tooltip which is slightly annoying though.