Advice please on my IP in Melbourne south east

Hi all,
I hope I could get some advise on my current IP.
Been following this awesome forum and learnt quite a bit from here.

I have a 3 bedroom unit (2 bathroom and 2 carspace) in Melbourne south-east (Clayton) which I have been holding since 2010.
With the current real estate craziness, been approached by a number of agents but also tempted by the number of sales around the area.

Rough rental yield is around 4%
Agent advised me I could get around high 7 or early 800k for it.

Currently, my long term tenant has advised me that they are planning to move on their new purchase property and looking at September 2021 as moving out date.

Now Im currently torn should I hold on to it or sell it ?

I know current market there is quite hot, but my concern is if I decide to sell I'm not sure what September market is normally like ?
Also lots of agent advised me the rental market has been quite "cold" currently so perhaps its better to cash it in.