My first son Ryan took his first steps at 10.5mths and was fully walking within 3 weeks of those first steps. Jayden took his first steps at 12mths but it wasn't until he turned 14mths that he was walking all the time so has only been fully walking for a couple of weeks now. I found however that Jayden being that bit later in his walking is a lot more sturdier in his walking and has had less falls and trips and tumbles than Ryan in those first mths of walking. Both mine spent about 2mths before taking their first steps cruising the furniture and were standing unaided probably a few weeks before their first steps as a guide though.
Let us know how your son goes, he doesn't sound too far off if he has the stability to stand unaided now.
Ryan (2) & Jayden (18mths)