My child is 9 months and is really tired and warm. His temp is 100.8. What should I do?

Watch and give... ...Fluids. In a sick child, other factors (such as activity and hydration) are more important than fever.
See Doctor. Qwhen an infant has fever you need to have him seen by your pediatrician. Low or high fever, it does not matter. Fever indicates an illness and needs to be seen to determine if he needs other treatment.