I won't recommend specific hoods that I haven't owned. Performance requirements first, cost vs. aesthetics to meet performance second.

Assuming a wall hood...

Overlap is needed front-to-back as well as side-to-side. Assume a hood entry aperture of 42 inches by 24 inches (from a 27 inch deep hood). This is a hood entry aperture area of 7 square feet. You will need 90 CFM/sq.ft. for containment of hot gas combustion products and hot oil from stir-fry. So the requirement is to be able (on high) to pull 7 x 90 = 630 CFM.

To do this with typical pressure losses in baffles and ducts, a 900 CFM rated blower will likely be required, consistent with your plan. However, this assumes that the house interior pressure is not reduced (relative to outside) by more than a few hundredths of an inch of water column. Most code authorities now-a-days will be enforcing make-up air (MUA) above 400 CFM (rated). You will need either a large duct opening outside with damper and minimal filtering (perhaps dumping air into a mud-room or basement with a powerful enough heater, or a powered MUA system with filtering and heating, depending on environment. The latter alone will eat your budget.

For the hood itself, one is best served by a commercial-hood-inspired configuration (often called "Pro") with a capture volume before the filtering and baffles for filtering. Ducting out the wall or up through an attic are both appropriate, but using a remote blower and intermediate silencer will yield a lower noise configuration if enough duct length is available. No matter which duct layout is chosen, capture volume and baffle filtering will preclude a thin under-cabinet hood.

Bottom line, a kitchen ventilation system suitable for the specified range may not cost as much as the range, but will not be far behind if the residence is to be kept free of greasy wet cooking effluent and the hazards of dropping your house pressure are to be avoided.

No under the cabinet hood with that range and 900CFM is pushing it and of course you need MUA . Stir frying needs a lot better venting and yes your ducting needs to be 8-10” I like vent-ahood I also do a lot of stir frying mine is 1200CFM over a 36” all gas range with a stir fry burner. Even at that I find the steam and oil seems to get everywhere to some degree. It is also best to be venting directly outside not with twists and turns in the ducting this is IMO one of the first things i discuss with clients when designing kitchens,

Your venting budget needs to equal your range budget. You will require Make Up Air. If your budget can’t handle the proper required venting, then give up doing a pro style range.

Thank you all for your comments. You're right I should increase my budget for the hood. After more research, I'm debating between wall-mounted Thermador 42" range hood with 1000 CFM blower vs. Vent-A-Hood 42" with 900 CFM. Pricing is about the same. Please share your thoughts on the hoods.

https://media3.bsh-group.com/Documents/MCDOC02811673_PH42GWS-27-INCH-DEPTH-WALL-HOOD-42-INCH-WIDTH-Specifications.pdf

https://www.ventahood.com/index.php?option=com_content&Itemid=333&id=361&view=article&modelsku=NPH18-342

Thank you for your help.

The Thermador hood for sure. It has good dimensions to provide good coverage of your range, and it has baffle filters. I like its straightforward pro look too. I wouldn’t want to pay for the “Thermador Connected Experience by Home Connect“. Sounds gimmicky - I don’t know why you would need connectibility for a hood, seriously. If you can find the same hood without that, I’d get that. Ventahood may work well, but they are a PITA to clean. Don’t let the salesperson try to convince you it’s a breeze to clean a VAH hood; it’s not.

Edited to add: Both of those hoods are 18” tall. If you install one under your cabinet, how much space will you have between your rangetop and the bottom of the hood? That distance needs to be somewhere between 30” and 36”.

The blowers for the two candidate hoods likely have different fan curves. VaH avoids the pressure loss of baffles, but pays for part of that with the squirrel cage blower having less tolerance for pressure losses elsewhere in the system, i.e., ducts, roof cap, imperfect MUA. You will need to have someone evaluate the total losses you might have and then access the Thermador hood fan curve (if available) to find the predicted actual flow rate (hopefully over 630 CFM) and compare the result to that predicted by the tabulated data at VaH for their actual flow rate with relevant pressure losses if a VaH hood were installed.

Volumetric flow rates aside, my preference is for baffle filtering and the simpler cleaning process that should apply when the baffles have been removed to the dishwasher and one has to reach up into the hood to clean accessible surfaces. If one is into the aesthetics of looking up into a hood, baffles should win over blowers.

Last, VaH hoods with their interior blowers cannot be further quieted, whereas a conventional hood with a remote blower allows the use of a silencer to make even full speed operation tolerable (if duct length and clearance allow).