Alibus Shuttle from Malpensa to Stresa

MXP is not generally crowded, actually it’s very empty and underutilized since Alitalia abandoned it as its hub, so, in my experience, arrival procedures have been very fast. The problem however might arise if your plane arrives late. On intercontinental flights it’s not unusual to accumulate a little delay, and all you need in your case is just 15 or 20 min delay, to make it difficult to make that bus. But give it a try. If for any reason you miss it, just take a taxi to the GALLARATE train station (10-15 min away), and catch a train to Stresa from there. Gallarate to Stresa is a 35 min train ride and trains are frequent.
The taxi to Gallarate is kind of pricey given the short distance (about 30€-35€) but then the train is only 5€ pp.
There is also a bus from MXP to Gallarate station, but it will take a bit longer (almost 30 min) than the taxi because it makes a few stops. But if it’s more than one person the taxi is not a bad deal, because I think the bus is about 10€ pp.

Train timetable (Gallarate to a Stresa) below:
www.trenitalia.com
Bus MXP to Gallarate below
http://www.airpullman.com/static/upload/ora/orari-gall-mxp-castel--dal-01-03-14.pdf

If I am reading the schedule correctly, the Alibus leaves from Terminal 1 at 8:40 and 11:40 and take 50 minutes to get to Stresa.
http://www.safduemila.com/alibus-2018-malpensa.lagomaggiore.html

Sam is correct.
So your choice is either the taxi+train via Gallarate I gave you above, or wait until 11:40 for the Saf2000 Alibus.

I took the 11:40am Alibus after a flight that arrived around 9:30am. There’s not much to do in that small airport, but there’s seating inside where you can see the bus stop. I found the Alibus to be a very nice option. I was picturing a large bus with suitcases underneath, but it was more like an airport shuttle van with a polite driver.

Personally, I think you probably could make that first one.

Enjoy your time in lovely Stresa!

I love Malpensa. It's sparkling clean, easy to navigate and has a gelateria! (You can while away some time there if you end up waiting for the later bus.)

I just did this. It didnt take long to get through but I came through Zurich. The bus was exactly on time and left promptly. Right outside rhe airport. Stresa is lovely. Enjoy.